People are frequently asking "Does this work on a ?" or "My color wires are different - which ones do I use?". I don't have the ability or time to answer this, nor does anyone else. What I recommend is you google your car's oxygen sensor and see if you can find a wiring diagram or at least find out how many wires. This fix probably only works for a "narrow band" sensor which can have 1-4 wires. There's a type called "wide band" which has 5 or 6 wires and they apparently use current. This fix will not work because it only regulates voltage and not current. You need to find the two wires that carry the actual o2 sensor and ground (and not the heater or any other signals). Failing that, it's pretty easy to figure it out with a voltmeter. Either bench test it as shown, or unplug the sensor and test the pins with the car running (which I don't recommend for many reasons but it can be done). You want to find the two wires that have a voltage fluctuating between 0-1V with a cycle time of no less than 1 second and ideally much slower. Here's what I know about the number of wires and what they do: 1 wire (just voltage and use chassis ground), 2 (voltage & gnd), 3 (voltage, gnd, heat), or 4 (voltage & gnd, heat & gnd) wires. Good luck, and you do get it to work, please post the year/make/model and wire colors you used.
Easy fix for the soldering issue, use a butane soldering iron and dip it in solder flux before you solder. It uses a lot less heat and the solder bonds right away. An old school soldering trick I learned from my Korean War veteran electrician father.
Actually, years ago I tried fixing a damaged wire on an oxygen sensor and came upon the same problem. The wires appeared to be some type of stainless steel and the solder would not adhere to them. I had to crimp connect the wires.
What was the next size cap that you used, you said it fast, I hit the rewind button, but no luck. Thanks, it works great, still can't dismiss the light. 97 GMC k 5.0. thanks
Thanks SOOOO much for this video! I have a 2001 Tundra V6 with CA emissions. Got a P0420 fault code and tried several ways to repair it. At the end of the day, I did not want to spend $1000 on a new OEM catalytic converter. So I tried this and it work! I put on a code reader after 10 miles of intstalling the "filter" and it showed no codes! I went to get it tested after 9 months expired plates and it passed and I was finally able to get my plates renewed! Steps I tried prior to this tip: 1. Replaced downstream O2 sensor 2. Used CataClean 3. Re-moved front cat (not rear) and soak in soapy water overnight. replaced cat with OEM gaskets. 4. Replaced upstream O2 sensor. 5. Finally installed this filter and it worked!
hey, did u install the resistor mod for both banks? My 2003 Odyssey v6 is throwing slow response p0139 after installing it on bank 1 only. I wonder if the ecu compares it to the other bank..... I'm going to be trying out lower capacitor value to 1.5uf.... Im at 3.3uf and it's still showing slow response
@@masmagalingako I have 07honda civic hybrid California Car did hack. P0420 code clear but after 40 miles I have p0139 now Have anyone able to clear this code if so how and what resistor and capacitor is right value
@@fosso67 I got mine working by jus using 2 resistors, 180k and 1megOhm. No capacitors. Honda at least my 05 odyssey uses wideband o2 sensor for the upstream. So slowing down the response with the capacitor will only cause a Slow Response fault code. What worked for me is a voltage divider network where the o2 signal voltage is dropped down by approximately 10%, such as 0.8 now reads 0.72 therefore reads a bit leaner. My van now always clears all of the emmissions code.
@@arnoldg3076 Thanks for posting this. I've been looking for answers to my 2006 Tundra P0420 and lots of other forums and posters talk about how the newer "wide band" sensors are immune to this fix. Can you expand a little more on how the two resisters work on wide band? Also, how did you wire them? In series with megaohm first and 180k second, or vise-versa?
Passed Emissions today on a 2001 Toyota Sienna with this strategy. Thanks a lot. I should share some details. When I soldered in the 4.7 uF capacitor and 1 megaohm resistor I got p0136 code (like a low voltage code on o2 sensor). Tore it all out and resoldered a breadboard instead (the o2 sensor connector is inside the cabin underneath the passenger seat as opposed to underneath the car). On the breadboard, I eventually used a 4.7 uF capacitor with a 470 kilo-ohm resistor instead. Although I didn't need to, using the breadboard allowed me to experiment with different capacitor and resistor pairs which you might need to do depending on your vehicle.
I have been suffering the p0420 on my mk3 Toyota mr2, tried to get the o2 sensor out and it was solid! to solder it in place was not practical so...solution: I chopped the plug and the socket off a scrap car and made an adaptor like section, just plug and play. I cleared the codes and have gone 50 miles so far (previously I would get 20 miles and mil light on), no mil light, no pending codes and my scanner says its all good. THANK YOU SO MUCH! I can get the bits and do the work but its clever guys like this that make it possible. thanks again.
Thanks for that helpful hint and I'm glad it worked for you. A number of people seem to have sensors that have seized. That's another good reason to solve it with this circuit rather than a spark plug extender.
Awesome how to video. Worked like a champ on my girlfriends Mazda 626. The Sauder was definitely a pain but after clearing the codes and driving 20 miles all readiness monitors had cleared. Going for inspection tomorrow. Thanks!
You might need to drive some more before inspection. The computer records if you reset the code manually and there's some unclear set of circumstances that have to happen before the computer will say that the all clear is legitimate. In general, I'd say you need to drive 75 miles before doing an inspection, otherwise you risk the possibility of them sending you home to come back. If you didn't clear it and it cleared by itself then you're fine going in anytime.
Well my scanner has a built in emissions tester and says Its clear to pass. But in North Carolina only 6 of 8 readiness monitors have to be complete to pass inspection. Thank you for your input and thank you for this video. Gained me some time in replacing the 400 dollar cat on this car.
2008 BMW 328xi - I was seeing .750v to .850v on both rear o2's. After this mod, .450v to .650v. I used 1M 1/4 W resistor and a 4.7uf 50v capacitor. Worked perfectly! Bought the car running pretty roughly. Spark plugs were shot. 1 bad fuel injector. Replaced the coils and 2 front o2's for good measure. Runs rock solid but still had the rear O2 faults. This fixed it. The spark plug non-foulers did NOT fix it.
Thanks for the video, It is greatly appreciated!! Keep making content! I do a lot of industrial and automotive electrical work, and constantly deal with solder joints on wire splices that won't flow out correctly. I always try first with flux but if the normal routine fails try this.. Clean the wires by scraping with razor blade, you can also use a wire brush or scotchbrite. Scrap/brush towards the end of the wire, ensuring you get all surfaces especially if it is a braided wire.
For people with the grey white and black wires. Grey is ground, takes the negative end of capacitor. Black is signal. Grey also takes the resistor, no resistor on black wire.
Will the resistor go before or after the capacitor on the gray wire? On the O2 sensor side or the ECM side? Thank you in advance. I installed the way it shows in the video and I’m getting a high voltage code. I’m assuming this will fix my problem.
just did this method with exact same type and ratings of resistor and capacitor on a Volvo xc90 v8 which uses a Yamaha engine, aisin/denso electronics (same as toyota.) It gave me code p0157, o2 circuit low voltage after 30 miles. now I have two problems. awesome!
I had a similar code. 100k resistor (and 1uf cap, but that shouldn't impact anything) raised my max voltage from .525v to .74v. (acceptable range is .605-1v in my Highlander.) I was also failing O2 time test cycles, so I reduced the cap as well so voltage would fall a little bit faster.
@@daddyosink4413 no i just did this mod and i have never gotten a check engine light. Just follow the mod and clear the check engine light. You will be set.
@@KKE1978 I have a PHYSICALLY failed cat.... like the "rock" has fallen apart and is obstructing exhaust flow making the engine run rough... I either have to remove/replace it, or gut it. As long as this mod will keep the light off and the computer happy I'm good. 😉
Thanks MITEEman, I bought a used 2004 fx35 last year and it failed smog check for P0138 and P0158 which are the post CAT o2 sensor issues. I went ahead and changed them both and I found out that it made no difference. When I delved into it a bit more I realized that all 4 o2 sensors once in operating temperature just show a steady voltage, the post CAT sensors go to 1.275 volts and max out, and B1 S1 is at .3 V and B2 S1 is at .64 with .01 v oscillation. When I accessed the ECM to see what is going on, I found that someone had simply joined the wires between S1 and S2 on B1 (and not B2). For the life of me I cannot figure it out why would anyone do that and why would ecm accept this. BTW, the car runs smoothly and aside from the "service engine soon" light on there are no issues. I also verified all 4 o2 sensors they are fine, even the original sensors that I replaced were fine. Anyone out there has any idea what is going on. I hate to revert it back to what I think it is supposed to be and find out now that the car is not running smoothly anymore. I have to point out that mileage is not that great 14-17 mpg. I unplugged B1 S1 and drove it and it still worked but not smoothly, it got slow to respond to acceleration.
I followed the directions exactly and it worked for me. 2002 Hyundai XG350, 65k miles with persistent P0430. 1000 miles later and no codes or check engine light. TX State inspection passed. You gotta do your own research on your specific car to determine which O2 sensor needs modifying, and which wires are what.
Can't believe this actually worked on my '99 Suburban!! I could not remove the O2 sensor even with correct tools. Thanks so much for the well explained vid!!
Liquid soldering flux is your friend, as is alcohol for cleanup. Oxygen sensor wire color codes are easy to find online which is also handy if you have a good donor from a different vehicle with a plug that doesn't match since you can swap plugs. I potted my resisitor and capacitor in epoxy then taped thoroughly over that.
The upstream sensor 1 is as you describe - it's feedback to the engine for how to adjust the rich/lean. You don't want to modify that one. You are going to modify the downstream sensor 2 (installed on or after the catalytic converter) which tells the computer that the catalytic converter is evenly catalyzing the exhaust as demonstrated by a steady o2 range.
What would happen if the upstream was modified ? I have a minor exhaust leak at the header. I did the trick and my gruñe economy has gone up and the engine light is off
I installed a wideband oxygen sensor for my primary that has a 0.1-5.1v range for my gauge and a 0.1-1.1v range for my ECU. Since I didn't want to have a 2nd bung for another primary oxygen sensor I just removed the stock one, and to avoid a CEL because I couldn't signal that the heater was working with the wideband, I just put 2 10ohm 1 watt resistors in line for the heater circuit. I used the stock oxygen sensor harness by cutting of the old sensor and using a male and female connector I ran signal from the wideband to the harness and to the ECU and then with the two heater wires I ran said resistors. No CEL accurate fueling and the ability to see what my AFRs are. This is for a 1997 Honda Prelude Base Model (Non-SH). I imagine this will work for someone with the heater CEL code and nothing else.
so cool to find this, 7 years later im about to try something similar on a 2012 chevy sonic,hehe. got some resistors and diodes around and im gonna give it a try.
Tried on 2000 jetta 2.0 with p0422 code(main catalyst below threshold bank 1). The p0422 code went away and created a p0140 code. However the spark plug defouler worked perfectly fine. Also look into angle spacers for o2 sensors for another fix.
You should rev it to 2000rpm to get quicker results after the solder. Great vid, I'll be doing this in a few days. Im useing 1 m ohm resistor, and 1 uf 50V capacitor
2:16 Thanks for posting the two Dorman non-foulers together. I need the longer of the two and nowhere but HERE did i find the difference. Even the Dorman website was useless in including length detail.
I had code p0136 after doing this. I just took it apart again to double check. I don't have the code reader that shows signals or lines, so I'm going to rely it's correct. I had both oxygen sensors replaced last year. My catalytic converter looks in great shape. No odd discoloration, or smoke of that sort. I will check that the connector is all the way in. Will be keeping my fingers crossed and letting you know the results soon.
Worked perfectly for me 1M ohm and 4.7 cap. 2002 Tacoma 2.4L. Catalytic monitor is ready after about 20 miles and NO check engine light . Thank u so much
i tried the adapter route and it rusted out in two years and sensor fell out. threads still in exhaust pipe. so if you do this make sure you replace the adapter every year. it will rust right in half pretty quickly.
Would this concept work on a header that delete's the CAT entirely? that is, leave the lambda where it typically is a the bottom of the header prior to the flange tot he midpipe and simply use the resistors like you do here to lower sensor re-fresh speed to the degree that the ECU believes the CAT is still in place?
I did this on a 2002 Toyota Sienna. It had p0420 code before. After modification it gave p0136. I figured out that this video is not correct for all vehicles, the Toyota sensor required the resistor be put on the signal ground wire (the white one). Not the blue one as shown in this video. After moving the resistor to the white wire this was a total success, it's been 300 miles and no codes.
Every o2 sensor can have different color wires, so perhaps you needed to move yours to the white wire but I would definitely say that doing this mod to the "signal ground" is NOT the right thing to do in any general sense. I'm not clear what you did with the capacitor, but moving the resistor to the ground *may* have raised the voltages for the output across the board. In some cases that might help, but certainly not a good general recommendation. This mod is trying to smooth out the curve whereas you raised the curve. The computer is checking if the curve crosses a certain voltage fewer times than the upstream sensor, and in some cases moving the curve up may also solve the problem, but I think that's a fluke and don't recommend it. The p0136 means sensor malfunction. That again indicates to me that you used the wrong wires. In particular, it flags the o2 sensor heater wires, so I believe your blue wire may have been one of the two heater wires. I looked up your model and it uses an OEM Denso which should be the same colors as mine. However, perhaps your o2 sensor was an aftermarket? Bottom line, I DO NOT recommend making this change, but in some cases I can see how it might possibly help (but more likely is not going to work). Given the P0136 code it's pretty clear that the mod was done incorrectly on the heater wires instead of the signal wires.
Nope, I did not have the colors mixed up. Checked everything with a meter. The black wires are for the heater. The blue wire on mine is positive and white wire is infact the signal ground (-). On my vehicle this is the wire (ground) that outputs the signal after leaving the sensor. limiting or "smoothing" as you put it. That signal puts the system in range. It checked out perfectly in range with the OBD2 scanner.
I made-up and installed 2 modified O2 sensors for a 2004 GMC Yukon XL 6.0L, B1S2, & B2S2. This smoothed out their signals to mimic good cats. However, P0136 and P0156 have now failed. These are the O2 sensor performance codes. The diagnostics passively monitors/tests the transitions below 350 mV and above 709 mV. If the ECM/PCM detects the passive tests have failed, the control module will force the air-to-fuel ratio rich and/or lean. The control module then waits for a predicted response from the HO2S. If the HO2S voltage transitions below 350 mV and/or above 709 mV. I wonder if different resistor and/or diode values can pass the P0136 and P0156 tests.
Nicely done video, and you are correct, this will "fool" the computer...sort of. The computer will show this test as "incomplete" and it will stay that way. Eventually, and it can takes months, you will most likely get the light back on with codes P0144 and P0145 which are directly related the voltage sensing of the O2 sensor. In California, your car will not pass due to the incomplete, but your light will stay out for a while.
The wires coming from most O2 sensors is stainless steel. This is usually difficult f not impossible with out using the correct solder, and flux in combination. That is why crimp on connections are used with most universal replacement O2 sensors. Tim
No. The upstream sensor controls the fuel trims for the engine. The lower oxygen sensor monitors the cat. The point of this is to trick the oxygen sensor to think the cat is good.
Thanks for the clear video. I am going to try this on my Fiesta ST MK6.5, since my Mongoose de-cat system occasionally triggers the MIL-light (low catalytic function). All sensors seem to be working, but for the sake of keeping this light out I will try your solution :-)
I had a P-0420 steady in my 2004 Toyota Sienna mini-van for the past year. I tried the fix as posted in the video.l I purchased the parts from my local Radio Shack and wired them as shown in the video. It did smooth out the response of the Bank 2 downstream O2 sensor. It was evident by graphing the two downstream O2 sensors. The modified sensor was much slower to react than the unmodified downstream sensor. However, the van would not pass the O2 readiness check and soon the CEL illuminated with a code P-0156 "O2 Sensor Circuit Bank 2 Sensor 2". I cleared the code and it came back on the very next drive. Thus, I soldiered the O2 sensor wires back to factory condition and installed the no-foulers as advertised in the video. The O2 sensor readiness passed in the first five minutes of driving. I have been driving the van for two weeks now with no check engine light BUT the catalyst readiness monitor is still INC after two weeks of driving. In Texas, you are allowed 1 INC readiness so, it passed this year's inspection without any problems. I don't know how long it will take for the catalyst readiness to turn to OK. Some people say it could take up to a month for this to turn to OK. I have no pending codes so I think it will be just a matter of time before the catalyst monitor changes from INC to OK. This van has 330,000 miles. I suspect the catalytic converter is most likely dead but a new one is cost prohibitive when compared to the value of the automobile. No-foulers it is for now.
+Tim Plasek .... FYI, Catalytic converter test runs at highway speeds, normally between 55 - 60 mph (can vary my make, model and year). Must be fairly steady speed for several minutes, and oxygen sensor monitors must have already been run. If you normally drive faster than this (most do) the cat test will have a hard time running in a short time period. I'm a shop owner / operator and often take problem vehicles for drives and then in for the OBDII emissions test as I can get them through where regular driving they will fail.
I've got a what I think is a denso in a '13 outback. I have a oil burner and I think it messed up my cat. By 125k miles I was getting the p0420 code. I was getting the code maybe every couple weeks. I went ahead and gutted the cat, because my mileage had dropped from 27 to near 25mpg over the last few months. I tested the O2 sensor like you did with a torch and I am pretty sure it is working. At any rate I did the resistor capacitor install like your video and now I am getting p0140 on the first drive out. I cleared it but it will probably return. I graphed my 02 sensor before the gut and it was sporadic jumping between .05v to .9v at 2000-2500 rpms.
I Performed this procedure on my downstream O2 sensor wires..closer to the connector rather than close to the sensor.Seems to be working just fine..I Used my Actron 9575 Scanner tool,to watch the sensors after the fuel system changes from open to closed loop.I have 2 new Os sensor's & I just installed new Injectors.running great, No Engine Light's.. I used a 1/2 watt (1) MegaOhm resistor,they didn't have the 1/4 watt..1-4.7 microfarad axial capacitor..Great Idea & It Works just fine to trick the (ECM) into thinking the 3way convertor is running at peak Performance.. Since even if the converter drop's to 95%,meaning if it loses 5% of it's performance It WILL throw the Code P0420 aswell as others.
@@gallantfox4776this code on my Highlander meant it was falling the O2 self-test-cycles. 100k resistor and 1uf cap fixed it for me. (Note, ideally you should read what test is causing the code.) OBDLink MX+ told me 1) I had too much voltage drop on Max voltage test cycles: .525v with acceptable range ~.6-1v. 2) I was failing the time (units were seconds) tests. IDK WTF they do, but I assume it meant the cap was keeping voltage up for too long. ¯\_(ツ)_/¯ Good luck.
Here’s how I finally got rid of my P0420: I have a 2007 Suzuki Grand Vitara that was getting the P0420 code. I decided to first try using an O2 spacer since they have been working fine for the last five years on another car I have, a 2000 Nissan Xterra. It passes inspection in California every two years with no problems - all monitors stay ready and no codes or check engine light. However, the spacer did not work on the Suzuki. I got a P0420 very quickly after two short drive cycles. I then tried a different spacer with a smaller hole but still got the P0420. Two more different spacers were tried (right angle spacer and 45 degree spacer) with no luck. I gave up on the spacers and switched to the low pass filter method described in this video. My first attempt was using a 1uf capacitor and a 1M ohm resistor. I got a code P2A01 for O2 sensor circuit performance. I then tried a 4.7uf capacitor and a 1M ohm resistor. Same code showed up - P2A01. This time I graphed the sensor and saw that it was never going below .22 volts. The Service Manual for the Suzuki says code P2A01 is issued when the O2 sensor “signal is more than 0.2V for more than 4 sec. even though vehicle is running with fuel cut mode below 4000 rpm.” This generally occurs when you are driving, for example, on a freeway and you take your foot off the gas to coast down the exit ramp. It can be simulated by idling the car and revving the engine four or five times and then letting go of the gas pedal. You should see the O2 sensor dip quickly to almost zero before climbing back up. I then tried a 270K ohm resistor instead of the 1M ohm along with the 4.7uf capacitor, hoping it would expand the amplitude range of the O2 sensor so it would go below .2V. The resistor helped some, but the O2 sensor barely got below .2V, and it was for just an instant no matter what the driving condition was. Next, I tried a 10uf capacitor and a 180K ohm resistor. This helped a lot and the sensor appeared to be working as it should as compared to the sensor on bank 2. I got no more fault codes or check engine light. However, the monitors would not go into ready mode no matter how long I drove the car. I tried one final time with a 10uf capacitor and a 100K resistor. Same result. After driving the car for over 300 miles, monitors were still not ready. Went back to trying a spacer again after reading that some people stuffed some stainless steel wool into the spacer tip to reduce the flow of exhaust gas reaching the sensor. Went for a test drive with my scanner attached not expecting much, but all monitors went ready in just a few miles. Came back home, checked for codes and found none, not even any pending codes. Restarted the car and this time drove on the freeway to see if any codes would set. Once again, no check engine light, no codes. It’s now been about 1300 miles and still no codes and all monitors are ready. My inspection comes up in about a month and should pass easily here in California using the spacer. The stainless steel wool and spacer was used with no resistor or capacitor.
How did you connect the resistor? I’m confused about if I need to cut the whole sensor wire in half or just make two little openings in the sleeve to connect each end of the resistor
Hi brother i have Suzuki Every 2010 model i face P0420 bank-1 and sensor have 5 wire's and bank-2 have 4 wire's . Plz help me Van give very bad fuel Average. New sensor is not available and used same sensor not working properly. I'm stuck in this Problem
I'm going to give this a shot as I had some of those capacitors lying around from a prior project. Just waiting on some resistors ... I'm not going to jump in and replace the cat when my car is running slightly rich and also suffering from vibrations at a specific RPM. This seems to indicate that something else could be the cause.
I have an 07 prius with an p0138 & 2237 after changing the o2 sensor twice and trying the resistor/ capacitor combination. The light came back on after 25-30 miles.
@@alexhuggins5924 I've changed both up and downstream sensors and the check engine light comes back on within thirty minutes. I was told it may need a new Catylitc converter
Toyota aygo 1.0 petrol 2008. 4.7uf capacitor and a 50kohm resistor and i got rid of all the bad codes. Took me a long time.to try what resistor was the right but found it and are very happy now.
Nimestä päätellen suomalainen🫵 niin että noilla arvoilla sait rauhottumaan? Mitätuota, muistakko noista piuhain väristä että miten ne oli? Ne signaalit meinaan -ja+ on ikävä kyllä itellä edessä myös tämmönen askartelu pösö 107😂
@@esa7269 auto jo vaihtunut tuon jälkeen. Videosta katoin ja tein. En enään muista noita + ja -. Hyvin kyllä pelas tuo hakki ja meni monta vuotta katsastuksesta läpikin
The capacitor will store a small charge and as the waveform drops the capacitor will discharge helping to even out the waveform resulting in fewer and more consistent changes downstream.
Bmw 550i 4.8 with this mod both sensors throw no activity codes and the voltage stays at .4 constantly, there is also a consistent heater circuit code on both (heater wires ohm test ok), reverted back to stock and back to a 420 and 430
Not sure if anything will work on this vehicle ive been through o2 simulators, non foulers, relocating the o2, and 90 degree spacers(smoke tested no exhaust leaks btw)
One thing i cant wrap my head around if anyone can explain, why did this mod turn my voltage graph from switching to flat line? It should have just spaced out the switch in voltage(again back to stock and back to switching fast)
I was getting the P0420 code. I did this on my 2003 Dodge Durango and I am now getting the P0138 code almost immediately. Signal voltage too high (over 0.9V). Where would it be getting higher voltage? A capacitor and a resistor should not raise the voltage right? I did not cut into the heater wires and made sure I insulated my connections.
I couldn't see which way the 1 m ohm resistor was put in or which way the capacitor was facing in your video,I have an 03 Nissan with 2 whites and one black one bank 2,bank one 2 blacks 2 whites
Yes, if you can find somewhere to make the modification that's easier to access, even inside the car, that would be better. On my Odyssey I was already down there so it was easy for me to do it right there and be able to test it.
I don't think the ECU will accept that but I haven't tried it. I would suspect it would flag the O2 sensor as failed but that's just a guess. Knowing the effort others have gone to in constructing a 555-timer based oscillator circuit, I assume the ECU needs to see variation of a manner consistent with normal function.
Help! 2011 equinox 2.4L I used this tutorial for my P0420, everything was fine got, got good reading. But as I was about to call it good. I noticed that at every cycle the voltage kept creeping up, until it just got stock at 1.275v. I thought the probably the resistor or capacitor went bad, changed them. But kept reading 1.275. Don’t know what to do next!!
I have a blk power+ and the signal grey - others are white heater wires so my signal wire is - do i still put the resistor on that one or how can i connect this
I want to clarify to everyone that this circuit will NOT fix a broken O2 sensor or broken Catalytic Converter. What it will do is prevent p0420 for a catalytic converter that is functioning but your computer is too sensitive. The ECM computer can't actually measure the smog components - only a mechanic can do that. Instead, your computer is programmed to interpret certain o2 performance characteristics as whether the catalytic converter is working at peak efficiency. If you only occasionally have p0420 and can make it go away depending upon the gas you used or perhaps a bottle of Chevron Techron, then this fix is highly likely to work. That's why I go through the effort to show you how to bench test your o2 sensor first because this isn't going to work if your o2 sensor doesn't work. Most people don't bother with that step. You can certainly bypass it and try the fix, but if you want help diagnosing further then you'll have to report either what your bench test results are or what your high end ODB scanner (ideally graphing) tells you the o2 bank 2 voltages are.
Hello MITEEman, I attempted this on a 2003 Honda CRV, The P0420 code has gone away but now I have a P0139 code which is described as (P0139 Honda - HO2S Bank 1 Sensor 2 Slow Response) have you ever ran into this problem? Thank you in advance
The1224ms No, I haven't seen it, but that code actually makes sense because this slows down the response of the waveform. You can speed up the response by using a smaller capacitor or resistor. Cut the value of either one (usually depends on what you can find in the store) in half and try again. The value of R x C is what determines how slow the response is.
MITEEman Hello MITEEman, my car has passed smog!!!! I did exactly what you suggested, I used the same resistor and a 2.2 microfarad capacitor, I have driven the car for about 100 miles with engine no light. I took it to smog it today and it passed, thank you for this video and the previous reply!
On that note it having the dealer check and see if there's an ecm update to (desensitize) the ecm, sometimes there reflashes out there and you won't know unless you bitch about a certain problem
4.7 uF was actually too high for me. I eventually got P0137, P0138, and P0139 codes indicating the o2 sensor wasn't working "fast" enough. Had to swap it out for a lower 1uF cap.
@@brianmcconnell7346using the frequency cutoff formula 1/(2piRC) THE CAPACITOR IS IN MICROFARADS SO DECREASING IT, INCREASES THE OVERALL FREQUENCY RESPONSE.
Great fix but I’d want to know why my cat is below threshold, possibly a vacuum leak causing a rich mixture and excess fuel being burnt in the cat destroying it?
Hi - I did all this, O2 sensor voltage looked right. The Code went away...now the code is back after a month and will not read anything. I got "LINK ERROR" at two different shops... 2009 Subaru Outback. Please help
ok fixed that by blowing out the link and resetting the battery...now I'm getting p0140 (no O2 activity) connections are good, but IIRC, the voltage was just solid at .5v (not moving at all) is that expected??
Thanks for this video man, I did this mod on my Lexus to correct P0420 error. It has got rid of the P0420 error but now on the same bank I have an error saying O2 Sensor Circuit High Voltage. I have used a 1Mohm carbon film resistor and a 35V 4.7uF capacitor just like your video. But getting this new error. Can you kindly advise? Thanks
So after I solder in the resistor and capacitor into my downstream O2 sensors and confirm they are working properly and there are no codes. Can I go ahead and completely gut my primary catalytic converters? The reason I ask is as I am sure some of you know, when converters get old they can completely disintegrate the honeycomb inside the converter. This can lead to a clogged exhaust or even worse with the now VVT engines and there valve timing overlap between intake and exhaust valves, material from the catalytic converter can get sucked back into the piston bore and completely destroy the cylinder wall on 1 or more cylinders.
would it be possible to use this configuration on a $20 o2 harness extension? this would just plug in line and would make this possible to do without even having to remove your o2 sensor. thanks for posting the video!
Yeah, that is what I was thinking. My wires come up inside the vehicle and under my passenger seat. I would do the soldering of the components there, out of sight under the seat -- should not matter their distance a few inches down the line from the sensor.
I did the "spark plug anti fouler" trick on my downstream o2. I still get a p0420. 1995 Subaru 2.2. Unfortunately Radio Shack closed down 2 months ago where I live here in Alaska. Looks like Amazon it is. Thanks for the video!!
“Get it in the right place” as in the location on the wire or the correct wires to use? I’m looking to add long tubes and catted y-pipes to my silverado. I figured i can do this to the O2 sensor connector extensions with wire loom so it’s not as visible for when I have to get my truck inspected. I have to have cats and can’t use O2 sensor “extension/ spark plug fouler” and I can’t use O2 sensor simulators 🤔
You can do it anywhere on the wire as long as it's electrically the same as shown. Some vehicles even have access inside the cabin. I haven't used wire loom but as long as it's properly insulated and doesn't get too hot I think it would work.
Yup, basically fooling the computer by giving it the correct value. I did that on my trailblazer because of a low pressure sensor in the fuel tank indicated a leak. This was a major issue with all trailblazers. Mine didnt have any leak as per smoke test,no cracked filler neck. No bad charcoal canistor and no bad pressure switch in the tank. I added a capastor and a resistor to reduce the voltage to bring the value down to .5v ,no more light,no more code. I know many Trailblazers that had that issue.
There was a recall for that exact problem on my Cruze and a Chevy dealership did this for free I'm going to do a video on the problems you can run in within the first 22,000 miles sometime and I hope people tune in and I can save them a lot of money comment if you want to see it
Im running into issues doing this with a 2010 Lexus is250, bank 2 sensor 2 is showing pending low voltage code, and its showing code for high voltage bank 1 sensor 2. help please
Get an o2 connector from a "You Pull It" junk yard. Get the o2 side and the wiring harness side. Put MIL simulator between both connectors. This way you don't have to cut up an o2 sensor. Just put it between o2 sensor and wiring harness. Plug and play.
That's a great solution if you can get access to those connectors. If you have to buy them it's expensive and a hassle to make a cable. Even going to a junkyard, crawling underneath, and removing one seems like more hassle than it's worth for me. But it's a good idea if you have a junkyard near you and you like doing that work.
I have used the patch and fixed the cat low efficiency issue, no more CEL of it; however, I still have the heating element resistance too high error; replaced a new O2 sensor but still got the same error about heating element; wires are ok. After the research it seems to be the heating time that taking too long to reach the temp and triggered this 2D13 CEL. Any idea here how to fix it? Can I try with different value resistor?
Did not fix my 2007 Chevy Tahoe 5.3L got a P2A01 code O2 Sensor Bank 1 Sensor 2 Hope to get a reply . Used the 4.7mf and the 1olm resistor put in correctly the O2 sensors is just a year old. Not sure if i need different Capacitor or Resister?
Hello there nice work. I am having an issue with my 2002 dodge dakota 2002. I replaced alot of electrical parts on my vehicle. It used to not run right. I replaced the catalytic converters today. I bought 2 up stream o2 sensor and 2 o2 down stream o2 senors. However I still have a P0136 code even though I replaced the o2 sensor today. My wires are good. How do I trick the 02 sensor bank 1 sensor 2
I’m confused. Did you cut the whole wire and place the resistor between both cut ends or make 2 small splices, leaving the wire connected, and then connect each end of the resistor to the open spots?
Hi smal question please dit you do that on the sensor before or after the cata. Bank 1 en bank 2 i have to modefide sensor 2 and sensor 2 correct ? So i have to fix the 2 sensors after the cat ? (Bmw got 2 converters )
I tried this but with the resistor on it was giving me 1.25 volts which my other bank sensor is only giving me .75 so I got a new code. I took off the resistor and it dropped it to .75 only time will tell if the CEL comes back.
so my O2 sensor does not have a blue wire it's still four wires but it has two white wires and it then has a black wire and then a gray wire so that leaves me at a sand seal can you help me and explain to me what I should do to apply this fix?
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People are frequently asking "Does this work on a ?" or "My color wires are different - which ones do I use?". I don't have the ability or time to answer this, nor does anyone else. What I recommend is you google your car's oxygen sensor and see if you can find a wiring diagram or at least find out how many wires. This fix probably only works for a "narrow band" sensor which can have 1-4 wires. There's a type called "wide band" which has 5 or 6 wires and they apparently use current. This fix will not work because it only regulates voltage and not current. You need to find the two wires that carry the actual o2 sensor and ground (and not the heater or any other signals). Failing that, it's pretty easy to figure it out with a voltmeter. Either bench test it as shown, or unplug the sensor and test the pins with the car running (which I don't recommend for many reasons but it can be done). You want to find the two wires that have a voltage fluctuating between 0-1V with a cycle time of no less than 1 second and ideally much slower. Here's what I know about the number of wires and what they do: 1 wire (just voltage and use chassis ground), 2 (voltage & gnd), 3 (voltage, gnd, heat), or 4 (voltage & gnd, heat & gnd) wires. Good luck, and you do get it to work, please post the year/make/model and wire colors you used.
Easy fix for the soldering issue, use a butane soldering iron and dip it in solder flux before you solder. It uses a lot less heat and the solder bonds right away. An old school soldering trick I learned from my Korean War veteran electrician father.
Actually, years ago I tried fixing a damaged wire on an oxygen sensor and came upon the same problem. The wires appeared to be some type of stainless steel and the solder would not adhere to them. I had to crimp connect the wires.
@@paulstandaert2042 Aluminum wire doesn't like solder. Also anytime you solder you need to use Flux.
What was the next size cap that you used, you said it fast, I hit the rewind button, but no luck. Thanks, it works great, still can't dismiss the light. 97 GMC k 5.0. thanks
Thanks forr the tip!
@@jesseter24did it clear the p0420 code?
Thanks SOOOO much for this video! I have a 2001 Tundra V6 with CA emissions. Got a P0420 fault code and tried several ways to repair it. At the end of the day, I did not want to spend $1000 on a new OEM catalytic converter. So I tried this and it work! I put on a code reader after 10 miles of intstalling the "filter" and it showed no codes! I went to get it tested after 9 months expired plates and it passed and I was finally able to get my plates renewed!
Steps I tried prior to this tip:
1. Replaced downstream O2 sensor
2. Used CataClean
3. Re-moved front cat (not rear) and soak in soapy water overnight. replaced cat with OEM gaskets.
4. Replaced upstream O2 sensor.
5. Finally installed this filter and it worked!
Ummm I’m telling...lol
hey, did u install the resistor mod for both banks? My 2003 Odyssey v6 is throwing slow response p0139 after installing it on bank 1 only. I wonder if the ecu compares it to the other bank..... I'm going to be trying out lower capacitor value to 1.5uf.... Im at 3.3uf and it's still showing slow response
@@masmagalingako I have 07honda civic hybrid California
Car did hack. P0420 code clear but after 40 miles I have p0139 now
Have anyone able to clear this code if so how and what resistor and capacitor is right value
@@fosso67 I got mine working by jus using 2 resistors, 180k and 1megOhm. No capacitors. Honda at least my 05 odyssey uses wideband o2 sensor for the upstream. So slowing down the response with the capacitor will only cause a Slow Response fault code.
What worked for me is a voltage divider network where the o2 signal voltage is dropped down by approximately 10%, such as 0.8 now reads 0.72 therefore reads a bit leaner.
My van now always clears all of the emmissions code.
@@arnoldg3076 Thanks for posting this. I've been looking for answers to my 2006 Tundra P0420 and lots of other forums and posters talk about how the newer "wide band" sensors are immune to this fix. Can you expand a little more on how the two resisters work on wide band? Also, how did you wire them? In series with megaohm first and 180k second, or vise-versa?
Passed Emissions today on a 2001 Toyota Sienna with this strategy. Thanks a lot. I should share some details. When I soldered in the 4.7 uF capacitor and 1 megaohm resistor I got p0136 code (like a low voltage code on o2 sensor). Tore it all out and resoldered a breadboard instead (the o2 sensor connector is inside the cabin underneath the passenger seat as opposed to underneath the car). On the breadboard, I eventually used a 4.7 uF capacitor with a 470 kilo-ohm resistor instead. Although I didn't need to, using the breadboard allowed me to experiment with different capacitor and resistor pairs which you might need to do depending on your vehicle.
Im having same problem on 02 4cyl tacoma,was to lazy to try a potentiometer, will try the 470k.thanks
Thanks, this is really helpful info for me
Dude that is genius definitely doing it this way. Gonna bring the board up into the cabin if I ever need to change anything it'll be way easier
Agreed. Solder on a 0-1M ohm pot, not a resistor.
Voltage was low on my O2's max voltage self test with 1M. 100k and 1uf worked for my 04 Highlander.
I have been suffering the p0420 on my mk3 Toyota mr2, tried to get the o2 sensor out and it was solid! to solder it in place was not practical so...solution: I chopped the plug and the socket off a scrap car and made an adaptor like section, just plug and play. I cleared the codes and have gone 50 miles so far (previously I would get 20 miles and mil light on), no mil light, no pending codes and my scanner says its all good. THANK YOU SO MUCH! I can get the bits and do the work but its clever guys like this that make it possible. thanks again.
Thanks for that helpful hint and I'm glad it worked for you. A number of people seem to have sensors that have seized. That's another good reason to solve it with this circuit rather than a spark plug extender.
Awesome how to video. Worked like a champ on my girlfriends Mazda 626. The Sauder was definitely a pain but after clearing the codes and driving 20 miles all readiness monitors had cleared. Going for inspection tomorrow. Thanks!
You might need to drive some more before inspection. The computer records if you reset the code manually and there's some unclear set of circumstances that have to happen before the computer will say that the all clear is legitimate. In general, I'd say you need to drive 75 miles before doing an inspection, otherwise you risk the possibility of them sending you home to come back. If you didn't clear it and it cleared by itself then you're fine going in anytime.
Well my scanner has a built in emissions tester and says Its clear to pass. But in North Carolina only 6 of 8 readiness monitors have to be complete to pass inspection. Thank you for your input and thank you for this video. Gained me some time in replacing the 400 dollar cat on this car.
Hey is the hack still working good?
2008 BMW 328xi - I was seeing .750v to .850v on both rear o2's. After this mod, .450v to .650v. I used 1M 1/4 W resistor and a 4.7uf 50v capacitor. Worked perfectly! Bought the car running pretty roughly. Spark plugs were shot. 1 bad fuel injector. Replaced the coils and 2 front o2's for good measure. Runs rock solid but still had the rear O2 faults. This fixed it. The spark plug non-foulers did NOT fix it.
Thanks bud for making a comment I tried the non fouler and I thought it was me but I think it's the non foulers will try this on my 2011 BMW 328
Thanks for the video, It is greatly appreciated!! Keep making content! I do a lot of industrial and automotive electrical work, and constantly deal with solder joints on wire splices that won't flow out correctly. I always try first with flux but if the normal routine fails try this..
Clean the wires by scraping with razor blade, you can also use a wire brush or scotchbrite. Scrap/brush towards the end of the wire, ensuring you get all surfaces especially if it is a braided wire.
Wats the volt on the capacitor 4.7uf what is the volt
The voltage from the O2 sensor is 0 to 1 volt, so anything over that will be fine. @@jbelectrical6833
For people with the grey white and black wires.
Grey is ground, takes the negative end of capacitor. Black is signal. Grey also takes the resistor, no resistor on black wire.
Will the resistor go before or after the capacitor on the gray wire? On the O2 sensor side or the ECM side? Thank you in advance. I installed the way it shows in the video and I’m getting a high voltage code. I’m assuming this will fix my problem.
just did this method with exact same type and ratings of resistor and capacitor on a Volvo xc90 v8 which uses a Yamaha engine, aisin/denso electronics (same as toyota.) It gave me code p0157, o2 circuit low voltage after 30 miles.
now I have two problems. awesome!
Replace the 02 sensors and take battery cables off battery ten touch them together and then reconnect to battery start car see what happens
I had a similar code. 100k resistor (and 1uf cap, but that shouldn't impact anything) raised my max voltage from .525v to .74v. (acceptable range is .605-1v in my Highlander.)
I was also failing O2 time test cycles, so I reduced the cap as well so voltage would fall a little bit faster.
This is the best tutorial ever saved me over thousands on my CATs for a bmw. THANK YOU SO MUCH. It worked like a charm.
EKK status update? Did the light stay off of did it come back on eventually
@@youtubeisbroken241 stayed off..
@@KKE1978 did you gut/remove the cat? Mine has collapsed and I dont have $400 to spend right now because we are still laid off because of Covid...
@@daddyosink4413 no i just did this mod and i have never gotten a check engine light. Just follow the mod and clear the check engine light. You will be set.
@@KKE1978 I have a PHYSICALLY failed cat.... like the "rock" has fallen apart and is obstructing exhaust flow making the engine run rough... I either have to remove/replace it, or gut it. As long as this mod will keep the light off and the computer happy I'm good. 😉
Thanks MITEEman, I bought a used 2004 fx35 last year and it failed smog check for P0138 and P0158 which are the post CAT o2 sensor issues. I went ahead and changed them both and I found out that it made no difference. When I delved into it a bit more I realized that all 4 o2 sensors once in operating temperature just show a steady voltage, the post CAT sensors go to 1.275 volts and max out, and B1 S1 is at .3 V and B2 S1 is at .64 with .01 v oscillation. When I accessed the ECM to see what is going on, I found that someone had simply joined the wires between S1 and S2 on B1 (and not B2). For the life of me I cannot figure it out why would anyone do that and why would ecm accept this. BTW, the car runs smoothly and aside from the "service engine soon" light on there are no issues. I also verified all 4 o2 sensors they are fine, even the original sensors that I replaced were fine.
Anyone out there has any idea what is going on. I hate to revert it back to what I think it is supposed to be and find out now that the car is not running smoothly anymore. I have to point out that mileage is not that great 14-17 mpg. I unplugged B1 S1 and drove it and it still worked but not smoothly, it got slow to respond to acceleration.
Worked like a charm. Cost me 3$ at a specialty electronics store. Thanks !!!
This video needs to make a comeback
I followed the directions exactly and it worked for me. 2002 Hyundai XG350, 65k miles with persistent P0430. 1000 miles later and no codes or check engine light. TX State inspection passed. You gotta do your own research on your specific car to determine which O2 sensor needs modifying, and which wires are what.
Thank you, this was very clear, no tacky heavy metal music, just the facts ! And a great steady camera-hand.
Cheers, Don
Can't believe this actually worked on my '99 Suburban!! I could not remove the O2 sensor even with correct tools. Thanks so much for the well explained vid!!
what motor is in it
Correct tool = heat
Liquid soldering flux is your friend, as is alcohol for cleanup. Oxygen sensor wire color codes are easy to find online which is also handy if you have a good donor from a different vehicle with a plug that doesn't match since you can swap plugs. I potted my resisitor and capacitor in epoxy then taped thoroughly over that.
The upstream sensor 1 is as you describe - it's feedback to the engine for how to adjust the rich/lean. You don't want to modify that one. You are going to modify the downstream sensor 2 (installed on or after the catalytic converter) which tells the computer that the catalytic converter is evenly catalyzing the exhaust as demonstrated by a steady o2 range.
pretty good gas mileage... wish my outback got that
Cavalier Basketball team
What would happen if the upstream was modified ? I have a minor exhaust leak at the header. I did the trick and my gruñe economy has gone up and the engine light is off
The wires have a coating if you use a razor and scrape the wires the solder will stick really good
I installed a wideband oxygen sensor for my primary that has a 0.1-5.1v range for my gauge and a 0.1-1.1v range for my ECU. Since I didn't want to have a 2nd bung for another primary oxygen sensor I just removed the stock one, and to avoid a CEL because I couldn't signal that the heater was working with the wideband, I just put 2 10ohm 1 watt resistors in line for the heater circuit. I used the stock oxygen sensor harness by cutting of the old sensor and using a male and female connector I ran signal from the wideband to the harness and to the ECU and then with the two heater wires I ran said resistors. No CEL accurate fueling and the ability to see what my AFRs are. This is for a 1997 Honda Prelude Base Model (Non-SH). I imagine this will work for someone with the heater CEL code and nothing else.
so cool to find this, 7 years later im about to try something similar on a 2012 chevy sonic,hehe. got some resistors and diodes around and im gonna give it a try.
Tried on 2000 jetta 2.0 with p0422 code(main catalyst below threshold bank 1). The p0422 code went away and created a p0140 code. However the spark plug defouler worked perfectly fine. Also look into angle spacers for o2 sensors for another fix.
You should rev it to 2000rpm to get quicker results after the solder. Great vid, I'll be doing this in a few days. Im useing 1 m ohm resistor, and 1 uf 50V capacitor
Did the 1uf capacitor work for you
2:16 Thanks for posting the two Dorman non-foulers together. I need the longer of the two and nowhere but HERE did i find the difference. Even the Dorman website was useless in including length detail.
I had code p0136 after doing this. I just took it apart again to double check. I don't have the code reader that shows signals or lines, so I'm going to rely it's correct. I had both oxygen sensors replaced last year. My catalytic converter looks in great shape. No odd discoloration, or smoke of that sort. I will check that the connector is all the way in. Will be keeping my fingers crossed and letting you know the results soon.
prntscr.com/56676x This is a bosch sensor. I google the wiring so this should work If you guys have any suggestions. Please let me know, thanks.
Sorry to say it didn't work. I went like 50 miles or so and p0136 came on.
Hi I face the same scenario. Hope to try the adapter and see.
THANK YOU!!! Fixed my nephews 2000 4Runner in a parking lot during lunch. Smog passed and new tags delivered. No CEL for the last month...
Stace Williams what were the ratings on the cap and resistor you used?
I have an ‘01 taco I need to do this mod on
Worked perfectly for me 1M ohm and 4.7 cap. 2002 Tacoma 2.4L. Catalytic monitor is ready after about 20 miles and NO check engine light . Thank u so much
i tried the adapter route and it rusted out in two years and sensor fell out. threads still in exhaust pipe. so if you do this make sure you replace the adapter every year. it will rust right in half pretty quickly.
Would this concept work on a header that delete's the CAT entirely? that is, leave the lambda where it typically is a the bottom of the header prior to the flange tot he midpipe and simply use the resistors like you do here to lower sensor re-fresh speed to the degree that the ECU believes the CAT is still in place?
Was looking forward forward to see t he markings on the capacitors to see what directions they were soldered in .
Positive lead on the data wires, negative lead to ground/earth.
I did this on a 2002 Toyota Sienna. It had p0420 code before. After modification it gave p0136. I figured out that this video is not correct for all vehicles, the Toyota sensor required the resistor be put on the signal ground wire (the white one). Not the blue one as shown in this video. After moving the resistor to the white wire this was a total success, it's been 300 miles and no codes.
Every o2 sensor can have different color wires, so perhaps you needed to move yours to the white wire but I would definitely say that doing this mod to the "signal ground" is NOT the right thing to do in any general sense. I'm not clear what you did with the capacitor, but moving the resistor to the ground *may* have raised the voltages for the output across the board. In some cases that might help, but certainly not a good general recommendation. This mod is trying to smooth out the curve whereas you raised the curve. The computer is checking if the curve crosses a certain voltage fewer times than the upstream sensor, and in some cases moving the curve up may also solve the problem, but I think that's a fluke and don't recommend it.
The p0136 means sensor malfunction. That again indicates to me that you used the wrong wires. In particular, it flags the o2 sensor heater wires, so I believe your blue wire may have been one of the two heater wires. I looked up your model and it uses an OEM Denso which should be the same colors as mine. However, perhaps your o2 sensor was an aftermarket?
Bottom line, I DO NOT recommend making this change, but in some cases I can see how it might possibly help (but more likely is not going to work). Given the P0136 code it's pretty clear that the mod was done incorrectly on the heater wires instead of the signal wires.
it worked. passed test been a month now no codes.
Glad it worked!
Nope, I did not have the colors mixed up. Checked everything with a meter. The black wires are for the heater. The blue wire on mine is positive and white wire is infact the signal ground (-). On my vehicle this is the wire (ground) that outputs the signal after leaving the sensor. limiting or "smoothing" as you put it. That signal puts the system in range. It checked out perfectly in range with the OBD2 scanner.
Excellent.
I made-up and installed 2 modified O2 sensors for a 2004 GMC Yukon XL 6.0L, B1S2, & B2S2. This smoothed out their signals to mimic good cats.
However, P0136 and P0156 have now failed. These are the O2 sensor performance codes. The diagnostics passively monitors/tests the transitions below 350 mV and above 709 mV. If the ECM/PCM detects the passive tests have failed, the control module will force the air-to-fuel ratio rich and/or lean. The control module then waits for a predicted response from the HO2S. If the HO2S voltage transitions below 350 mV and/or above 709 mV.
I wonder if different resistor and/or diode values can pass the P0136 and P0156 tests.
This is what I'm thinking too. There must be a "perfect combination"
Nicely done video, and you are correct, this will "fool" the computer...sort of. The computer will show this test as "incomplete" and it will stay that way. Eventually, and it can takes months, you will most likely get the light back on with codes P0144 and P0145 which are directly related the voltage sensing of the O2 sensor. In California, your car will not pass due to the incomplete, but your light will stay out for a while.
So do you need all monitors set in CA to pass? I'm a PA emissions inspector and we can have all but 1 monitor set and all but 2 set if it's from 95-00
@@Zachattackisrad up till 03 you can have 1 incomplete monitor. On 00 and below I believe it's 3/4 of monitors are required.
You are correct. That’s what happened in my case. Engine light remains off but cat monitor does not set. Great video though.
The wires coming from most O2 sensors is stainless steel. This is usually difficult f not impossible with out using the correct solder, and flux in combination.
That is why crimp on connections are used with most universal replacement O2 sensors.
Tim
A flux pen really helped me get the solder to stick.
Applicable for d upstream sensor sir? Thanks!
No. The upstream sensor controls the fuel trims for the engine. The lower oxygen sensor monitors the cat. The point of this is to trick the oxygen sensor to think the cat is good.
Thanks for the clear video. I am going to try this on my Fiesta ST MK6.5, since my Mongoose de-cat system occasionally triggers the MIL-light (low catalytic function). All sensors seem to be working, but for the sake of keeping this light out I will try your solution :-)
I had a P-0420 steady in my 2004 Toyota Sienna mini-van for the past year. I tried the fix as posted in the video.l I purchased the parts from my local Radio Shack and wired them as shown in the video. It did smooth out the response of the Bank 2 downstream O2 sensor. It was evident by graphing the two downstream O2 sensors. The modified sensor was much slower to react than the unmodified downstream sensor. However, the van would not pass the O2 readiness check and soon the CEL illuminated with a code P-0156 "O2 Sensor Circuit Bank 2 Sensor 2". I cleared the code and it came back on the very next drive.
Thus, I soldiered the O2 sensor wires back to factory condition and installed the no-foulers as advertised in the video. The O2 sensor readiness passed in the first five minutes of driving. I have been driving the van for two weeks now with no check engine light BUT the catalyst readiness monitor is still INC after two weeks of driving. In Texas, you are allowed 1 INC readiness so, it passed this year's inspection without any problems. I don't know how long it will take for the catalyst readiness to turn to OK. Some people say it could take up to a month for this to turn to OK. I have no pending codes so I think it will be just a matter of time before the catalyst monitor changes from INC to OK.
This van has 330,000 miles. I suspect the catalytic converter is most likely dead but a new one is cost prohibitive when compared to the value of the automobile. No-foulers it is for now.
+Tim Plasek .... FYI, Catalytic converter test runs at highway speeds, normally between 55 - 60 mph (can vary my make, model and year). Must be fairly steady speed for several minutes, and oxygen sensor monitors must have already been run. If you normally drive faster than this (most do) the cat test will have a hard time running in a short time period. I'm a shop owner / operator and often take problem vehicles for drives and then in for the OBDII emissions test as I can get them through where regular driving they will fail.
I've got a what I think is a denso in a '13 outback. I have a oil burner and I think it messed up my cat. By 125k miles I was getting the p0420 code. I was getting the code maybe every couple weeks. I went ahead and gutted the cat, because my mileage had dropped from 27 to near 25mpg over the last few months. I tested the O2 sensor like you did with a torch and I am pretty sure it is working. At any rate I did the resistor capacitor install like your video and now I am getting p0140 on the first drive out. I cleared it but it will probably return. I graphed my 02 sensor before the gut and it was sporadic jumping between .05v to .9v at 2000-2500 rpms.
I Performed this procedure on my downstream O2 sensor wires..closer to the connector rather than close to the sensor.Seems to be working just fine..I Used my Actron 9575 Scanner tool,to watch the sensors after the fuel system changes from open to closed loop.I have 2 new Os sensor's & I just installed new Injectors.running great, No Engine Light's.. I used a 1/2 watt (1) MegaOhm resistor,they didn't have the 1/4 watt..1-4.7 microfarad axial capacitor..Great Idea & It Works just fine to trick the (ECM) into thinking the 3way convertor is running at peak Performance.. Since even if the converter drop's to 95%,meaning if it loses 5% of it's performance It WILL throw the Code P0420 aswell as others.
Does this work with a secondary air injection pump. I know the o2 sensor reads the flow of air from the pump, that passes through the cat.
I did all but getting a p138 and ecu code it’s 06 toyota tundra no idea now
@@gallantfox4776this code on my Highlander meant it was falling the O2 self-test-cycles. 100k resistor and 1uf cap fixed it for me. (Note, ideally you should read what test is causing the code.)
OBDLink MX+ told me
1) I had too much voltage drop on Max voltage test cycles: .525v with acceptable range ~.6-1v.
2) I was failing the time (units were seconds) tests. IDK WTF they do, but I assume it meant the cap was keeping voltage up for too long. ¯\_(ツ)_/¯
Good luck.
year / make on the car your working on plz
Here’s how I finally got rid of my P0420:
I have a 2007 Suzuki Grand Vitara that was getting the P0420 code. I decided to first try using an O2 spacer since they have been working fine for the last five years on another car I have, a 2000 Nissan Xterra. It passes inspection in California every two years with no problems - all monitors stay ready and no codes or check engine light.
However, the spacer did not work on the Suzuki. I got a P0420 very quickly after two short drive cycles. I then tried a different spacer with a smaller hole but still got the P0420. Two more different spacers were tried (right angle spacer and 45 degree spacer) with no luck. I gave up on the spacers and switched to the low pass filter method described in this video. My first attempt was using a 1uf capacitor and a 1M ohm resistor. I got a code P2A01 for O2 sensor circuit performance. I then tried a 4.7uf capacitor and a 1M ohm resistor. Same code showed up - P2A01. This time I graphed the sensor and saw that it was never going below .22 volts. The Service Manual for the Suzuki says code P2A01 is issued when the O2 sensor “signal is more than 0.2V for more than 4 sec. even though vehicle is running with fuel cut mode below 4000 rpm.” This generally occurs when you are driving, for example, on a freeway and you take your foot off the gas to coast down the exit ramp. It can be simulated by idling the car and revving the engine four or five times and then letting go of the gas pedal. You should see the O2 sensor dip quickly to almost zero before climbing back up.
I then tried a 270K ohm resistor instead of the 1M ohm along with the 4.7uf capacitor, hoping it would expand the amplitude range of the O2 sensor so it would go below .2V. The resistor helped some, but the O2 sensor barely got below .2V, and it was for just an instant no matter what the driving condition was.
Next, I tried a 10uf capacitor and a 180K ohm resistor. This helped a lot and the sensor appeared to be working as it should as compared to the sensor on bank 2. I got no more fault codes or check engine light. However, the monitors would not go into ready mode no matter how long I drove the car. I tried one final time with a 10uf capacitor and a 100K resistor. Same result. After driving the car for over 300 miles, monitors were still not ready.
Went back to trying a spacer again after reading that some people stuffed some stainless steel wool into the spacer tip to reduce the flow of exhaust gas reaching the sensor. Went for a test drive with my scanner attached not expecting much, but all monitors went ready in just a few miles. Came back home, checked for codes and found none, not even any pending codes. Restarted the car and this time drove on the freeway to see if any codes would set. Once again, no check engine light, no codes. It’s now been about 1300 miles and still no codes and all monitors are ready. My inspection comes up in about a month and should pass easily here in California using the spacer.
The stainless steel wool and spacer was used with no resistor or capacitor.
I have same question - did you use resistor and capacitor + distancer, or distancer with steel wool solely
@@gile11ubica spacer and steel wool only. No resistor or capacitor
Where did you go for smog check? The place I went failed me because they seen my spacer.
Wont the smog inspector see it if there a visual check
hey if i go to inspection with spacer does that gonna make my inspection failed and which one you recommend thank you
Now that works perfect, i went from throwing the p0420 every couple miles to now not having any.., works on a 98 honda crv LX
Did you use the same 1Mohm and 4.7uf cap to your crv i have issues here?
How did you connect the resistor? I’m confused about if I need to cut the whole sensor wire in half or just make two little openings in the sleeve to connect each end of the resistor
Hi brother i have Suzuki Every 2010 model i face P0420 bank-1 and sensor have 5 wire's and bank-2 have 4 wire's . Plz help me Van give very bad fuel Average. New sensor is not available and used same sensor not working properly. I'm stuck in this Problem
I'm going to give this a shot as I had some of those capacitors lying around from a prior project. Just waiting on some resistors ...
I'm not going to jump in and replace the cat when my car is running slightly rich and also suffering from vibrations at a specific RPM. This seems to indicate that something else could be the cause.
I have an 07 prius with an p0138 & 2237 after changing the o2 sensor twice and trying the resistor/ capacitor combination.
The light came back on after 25-30 miles.
Have you changed the upstream sensor. I have an 07 prius and I am just now replacing both o2 sensors at 323,000
@@alexhuggins5924
I've changed both up and downstream sensors and the check engine light comes back on within thirty minutes.
I was told it may need a new Catylitc converter
Toyota aygo 1.0 petrol 2008. 4.7uf capacitor and a 50kohm resistor and i got rid of all the bad codes. Took me a long time.to try what resistor was the right but found it and are very happy now.
Nimestä päätellen suomalainen🫵 niin että noilla arvoilla sait rauhottumaan? Mitätuota, muistakko noista piuhain väristä että miten ne oli? Ne signaalit meinaan -ja+ on ikävä kyllä itellä edessä myös tämmönen askartelu pösö 107😂
@@esa7269 auto jo vaihtunut tuon jälkeen. Videosta katoin ja tein. En enään muista noita + ja -. Hyvin kyllä pelas tuo hakki ja meni monta vuotta katsastuksesta läpikin
The capacitor will store a small charge and as the waveform drops the capacitor will discharge helping to even out the waveform resulting in fewer and more consistent changes downstream.
That's right!
Worked for me! Thanks for sharing this. My old civic is running great and I can't afford to replace the cat with an OEM one.
Bmw 550i 4.8 with this mod both sensors throw no activity codes and the voltage stays at .4 constantly, there is also a consistent heater circuit code on both (heater wires ohm test ok), reverted back to stock and back to a 420 and 430
Not sure if anything will work on this vehicle ive been through o2 simulators, non foulers, relocating the o2, and 90 degree spacers(smoke tested no exhaust leaks btw)
One thing i cant wrap my head around if anyone can explain, why did this mod turn my voltage graph from switching to flat line? It should have just spaced out the switch in voltage(again back to stock and back to switching fast)
I was getting the P0420 code. I did this on my 2003 Dodge Durango and I am now getting the P0138 code almost immediately. Signal voltage too high (over 0.9V). Where would it be getting higher voltage? A capacitor and a resistor should not raise the voltage right? I did not cut into the heater wires and made sure I insulated my connections.
I couldn't see which way the 1 m ohm resistor was put in or which way the capacitor was facing in your video,I have an 03 Nissan with 2 whites and one black one bank 2,bank one 2 blacks 2 whites
you can make those connections on the plug sensor side, it will be hidden and protected!
Yes, if you can find somewhere to make the modification that's easier to access, even inside the car, that would be better. On my Odyssey I was already down there so it was easy for me to do it right there and be able to test it.
I don't think the ECU will accept that but I haven't tried it. I would suspect it would flag the O2 sensor as failed but that's just a guess. Knowing the effort others have gone to in constructing a 555-timer based oscillator circuit, I assume the ECU needs to see variation of a manner consistent with normal function.
And that would ALSO fit under a seat.
SO I THE WHITE CIRCUIT CONSIDER NEGATIVE? to correct capacitor connection?
My wire are two white and one gray and one black. 2004 yukon XL gmc which do I use?
Help! 2011 equinox 2.4L
I used this tutorial for my P0420, everything was fine got, got good reading. But as I was about to call it good. I noticed that at every cycle the voltage kept creeping up, until it just got stock at 1.275v. I thought the probably the resistor or capacitor went bad, changed them. But kept reading 1.275. Don’t know what to do next!!
reduce the resistor - that will help voltage leak out faster
Can you get a link for the resistor
Some Toyota sensor connector under passenger seat work.some vehicles have metal bracket,covers connectors
Tried on a 06 camry 4 cyl but I got a P0144 after a few miles. Why is that? I used a 1M ohm R and 4.7uF capacitor.
P0430 came on every 50 miles or so after I did this it comes on immediately. What’s the problem?
Wireing backwards, probably
I have a blk power+ and the signal grey - others are white heater wires so my signal wire is - do i still put the resistor on that one or how can i connect this
which color is where you work in a honda civic 2003
I want to clarify to everyone that this circuit will NOT fix a broken O2 sensor or broken Catalytic Converter. What it will do is prevent p0420 for a catalytic converter that is functioning but your computer is too sensitive. The ECM computer can't actually measure the smog components - only a mechanic can do that. Instead, your computer is programmed to interpret certain o2 performance characteristics as whether the catalytic converter is working at peak efficiency. If you only occasionally have p0420 and can make it go away depending upon the gas you used or perhaps a bottle of Chevron Techron, then this fix is highly likely to work. That's why I go through the effort to show you how to bench test your o2 sensor first because this isn't going to work if your o2 sensor doesn't work. Most people don't bother with that step. You can certainly bypass it and try the fix, but if you want help diagnosing further then you'll have to report either what your bench test results are or what your high end ODB scanner (ideally graphing) tells you the o2 bank 2 voltages are.
Hello MITEEman, I attempted this on a 2003 Honda CRV, The P0420 code has gone away but now I have a P0139 code
which is described as (P0139 Honda - HO2S Bank 1 Sensor 2 Slow Response) have you ever ran into this problem?
Thank you in advance
The1224ms
No, I haven't seen it, but that code actually makes sense because this slows down the response of the waveform. You can speed up the response by using a smaller capacitor or resistor. Cut the value of either one (usually depends on what you can find in the store) in half and try again. The value of R x C is what determines how slow the response is.
MITEEman Oh ok, makes sense I'll give that a shot. Thank you for the reply!
MITEEman Hello MITEEman, my car has passed smog!!!! I did exactly what you suggested, I used the same resistor and a 2.2 microfarad capacitor, I have driven the car for about 100 miles with engine no light. I took it to smog it today and it passed, thank you for this video and the previous reply!
On that note it having the dealer check and see if there's an ecm update to (desensitize) the ecm, sometimes there reflashes out there and you won't know unless you bitch about a certain problem
hello my car is hyundai accent 2015 model There are 5 wires in the sensor, 5 pins red black gray yellow white which one should i wear
4.7 uF was actually too high for me. I eventually got P0137, P0138, and P0139 codes indicating the o2 sensor wasn't working "fast" enough. Had to swap it out for a lower 1uF cap.
How did you know a 1uF capacitor would be sufficient?
@@brianmcconnell7346using the frequency cutoff formula
1/(2piRC)
THE CAPACITOR IS IN MICROFARADS SO DECREASING IT, INCREASES THE OVERALL FREQUENCY RESPONSE.
Great fix but I’d want to know why my cat is below threshold, possibly a vacuum leak causing a rich mixture and excess fuel being burnt in the cat destroying it?
Hi - I did all this, O2 sensor voltage looked right. The Code went away...now the code is back after a month and will not read anything. I got "LINK ERROR" at two different shops... 2009 Subaru Outback. Please help
ok fixed that by blowing out the link and resetting the battery...now I'm getting p0140 (no O2 activity) connections are good, but IIRC, the voltage was just solid at .5v (not moving at all) is that expected??
@@hammerain93 some people were saying the resistor was too much resistance and stepped down to 100k
Many O2 sensors use steel wire .. try using silver solder, and has been said, use rosin flux
Yea those 02 sensor wires are different the solder just drips off them
I crimped my connections using a butt connector. Removed the insulation and cut it in half for a better fit.
Thanks for this video man, I did this mod on my Lexus to correct P0420 error. It has got rid of the P0420 error but now on the same bank I have an error saying O2 Sensor Circuit High Voltage. I have used a 1Mohm carbon film resistor and a 35V 4.7uF capacitor just like your video. But getting this new error. Can you kindly advise? Thanks
Did you find out the problem ?
About to try this out! Been running no cats for a while lol just tired of looking at that damn check engine light. Thanks for this tip man
Did it work
Could you please write down the exact amount of the resistor and the capacitor?
So after I solder in the resistor and capacitor into my downstream O2 sensors and confirm they are working properly and there are no codes. Can I go ahead and completely gut my primary catalytic converters? The reason I ask is as I am sure some of you know, when converters get old they can completely disintegrate the honeycomb inside the converter. This can lead to a clogged exhaust or even worse with the now VVT engines and there valve timing overlap between intake and exhaust valves, material from the catalytic converter can get sucked back into the piston bore and completely destroy the cylinder wall on 1 or more cylinders.
No, this is dependent upon your catalytic converter working. If your cat does fail this won't work anymore.
Just did this and now I'm having a hard time starting my car, would this drain my car battery?
4:45 I’m seeing where you put the resistor. Did you cut the sensor wire and then place the resistor in between where you cut the wire?
would it be possible to use this configuration on a $20 o2 harness extension? this would just plug in line and would make this possible to do without even having to remove your o2 sensor. thanks for posting the video!
Yeah, that is what I was thinking. My wires come up inside the vehicle and under my passenger seat. I would do the soldering of the components there, out of sight under the seat -- should not matter their distance a few inches down the line from the sensor.
Is there a setup to omit the sensor and just run the plug with the capacitor n resist?
I did the "spark plug anti fouler" trick on my downstream o2. I still get a p0420. 1995 Subaru 2.2.
Unfortunately Radio Shack closed down 2 months ago where I live here in Alaska. Looks like Amazon it is. Thanks for the video!!
Can you tel me exactly for wich line resistor should attached to sensor supply or sensor signal
“Get it in the right place” as in the location on the wire or the correct wires to use?
I’m looking to add long tubes and catted y-pipes to my silverado. I figured i can do this to the O2 sensor connector extensions with wire loom so it’s not as visible for when I have to get my truck inspected. I have to have cats and can’t use O2 sensor “extension/ spark plug fouler” and I can’t use O2 sensor simulators 🤔
You can do it anywhere on the wire as long as it's electrically the same as shown. Some vehicles even have access inside the cabin. I haven't used wire loom but as long as it's properly insulated and doesn't get too hot I think it would work.
Yup, basically fooling the computer by giving it the correct value. I did that on my trailblazer because of a low pressure sensor in the fuel tank indicated a leak. This was a major issue with all trailblazers. Mine didnt have any leak as per smoke test,no cracked filler neck. No bad charcoal canistor and no bad pressure switch in the tank. I added a capastor and a resistor to reduce the voltage to bring the value down to .5v ,no more light,no more code. I know many Trailblazers that had that issue.
Which diode should I use on an O2 sensor on an 01’ S10 V6. It only has 2 wires.
There was a recall for that exact problem on my Cruze and a Chevy dealership did this for free I'm going to do a video on the problems you can run in within the first 22,000 miles sometime and I hope people tune in and I can save them a lot of money comment if you want to see it
Im running into issues doing this with a 2010 Lexus is250, bank 2 sensor 2 is showing pending low voltage code, and its showing code for high voltage bank 1 sensor 2. help please
My sensor is bad, can I delete it with resistors?
Get an o2 connector from a "You Pull It" junk yard. Get the o2 side and the wiring harness side. Put MIL simulator between both connectors. This way you don't have to cut up an o2 sensor. Just put it between o2 sensor and wiring harness. Plug and play.
That's a great solution if you can get access to those connectors. If you have to buy them it's expensive and a hassle to make a cable. Even going to a junkyard, crawling underneath, and removing one seems like more hassle than it's worth for me. But it's a good idea if you have a junkyard near you and you like doing that work.
Does it matter if you put it in the front of the sensor or bottom wiring?
sorry it whas not clear to me if bot capacitor and resitor go on the same sensosr or one in upstream and other on downstream?
my opel corsa d have 2 o2 sensor what should I do. which sensor do i need to mod
Will this work on any car with a 4 wire o2 sensor? I have a 2008 Lexus is250.
I have used the patch and fixed the cat low efficiency issue, no more CEL of it; however, I still have the heating element resistance too high error; replaced a new O2 sensor but still got the same error about heating element; wires are ok. After the research it seems to be the heating time that taking too long to reach the temp and triggered this 2D13 CEL. Any idea here how to fix it? Can I try with different value resistor?
Did not fix my 2007 Chevy Tahoe 5.3L got a P2A01 code O2 Sensor Bank 1 Sensor 2 Hope to get a reply . Used the 4.7mf and the 1olm resistor put in correctly the O2 sensors is just a year old. Not sure if i need different Capacitor or Resister?
Hello there nice work. I am having an issue with my 2002 dodge dakota 2002.
I replaced alot of electrical parts on my vehicle. It used to not run right. I replaced the catalytic converters today. I bought 2 up stream o2 sensor and 2 o2 down stream o2 senors.
However I still have a P0136 code even though I replaced the o2 sensor today. My wires are good. How do I trick the 02 sensor bank 1 sensor 2
hi thanks for the great video where can i find the simulator ? thanks
I’m confused. Did you cut the whole wire and place the resistor between both cut ends or make 2 small splices, leaving the wire connected, and then connect each end of the resistor to the open spots?
This worked for my 2005 Lancer - but using 2.5 uf capacitor - the 4.7 did not work.
El capacitor será el de 2.2 UF o 3.3 UF de otro valor es casi imposible conseguir
Hello I did same application on 2006 toyota tundra 4.7 both sensor and getting ecu code can you advice me pls
Hi smal question please dit you do that on the sensor before or after the cata. Bank 1 en bank 2 i have to modefide sensor 2 and sensor 2 correct ? So i have to fix the 2 sensors after the cat ? (Bmw got 2 converters )
I tried this but with the resistor on it was giving me 1.25 volts which my other bank sensor is only giving me .75 so I got a new code. I took off the resistor and it dropped it to .75 only time will tell if the CEL comes back.
Did you figure out this issue?
so my O2 sensor does not have a blue wire it's still four wires but it has two white wires and it then has a black wire and then a gray wire so that leaves me at a sand seal can you help me and explain to me what I should do to apply this fix?