Holy AMAZING! You are so thorough and helpful with your teachings, thank you so much for taking the time to share and help others! You have a true gift!
Nice job with the diagnosis. Getting that old O2 out can be a struggle so it sure is good to be confident a new sensor will fix the problem. Makes the struggle worthwhile!
August, thanks for stopping by! As you know I've been following your arborist channel. Professionals like yourself show us how much better TH-cam videos can be, you raise the bar. I live in Victoria, BC, but have had a few occasions to visit your amazing Oregon.
Great video, that really helps me understand how this system works. Yet, I am still struggling to fix my O2 sensor problem. I have code P0161 (B2S2 heater circuit malfunction) on a 2001 Tundra 4.7L engine. I found a deal on an aftermarket L/R pair, so naively bought these and replaced both sides. After resetting the code, the check engine light came back on within 10 miles with the same code. So now I tested the resistance in the sensors I pulled and the ones on the vehicle: B1S2 15 ohms - Original OEM part B2S2 0 ohms - Original OEM part B1S2 11 ohms - Installed aftermarket part B2S2 0 ohms - Installed aftermarket part B1S1 16 ohms - OEM part B2S1 10.7 Ohms-Aftermarket part installed by previous owner I read this to say that the original B2S2 was indeed bad, that the new B2S2 is bad, and that the aftermarket parts I installed may have the wrong specs. I did not test them new. Also, the B2S1 may be failing. Could the wrong specs on the aftermarket part explain the apparent failure of the new part? If so wouldn't both go bad? Could there be something upstream causing the failure? Next, I tested voltage at the harnesses running a cold engine and sensor wires disconnected: B1S2 14V, but will not light a test light at the harness B2S2 14V, but will not light a test light at the harness B2S1 14V, WILL light a test light at the harness In all three of these, the test light does light up if I connect positive at the harness to the frame, showing the 'problem' is in the switched neutral. Does this mean there is wire damage? Or the ECU is malfunctioning? Or something else?
With such low resistance, the risk of high current damaging downstream parts is significant, so many PCM grounded circuits will shut down that function if resistance in the circuit is too low. In that situation you may need to erase the trouble codes before the circuit will work properly. I would buy one OEM sensor from the dealer, erase the codes before firing the truck back up, then see what happens. If it works, you could go ahead and buy the rest. An alternate possibility is that the driver (or ground wire to the PCM module) is fried, but I wouldn't jump to that conclusion yet.
@@spelunkerd Thanks for the quick response. I did figure out that the PCM shuts down the circuit, and tested it after clearing codes, but still haven't been able to get it to light a test light. The check engine light comes back on pretty fast. I have a sensor on order, and will repost when I get it installed.
@@michaelscheu672 That's concerning. You could check the fuse, and check the power and ground sources, perhaps even tracing it all the way back to the pcm to build evidence for a wiring problem along the way. Let's hope the PCM grounding driver isn't fried. Some of these produce a PWM square wave output, more prominent when the engine is cold, so I'd be testing with engine cold and codes erased. If your oxygen sensor has very low voltage, remove it before testing so that your test light won't be bypassed through a parallel low resistance arm.
@@spelunkerd Still waiting on the part, but in the meantime: The Fuse: I can't figure out which fuse controls the positive side of the sensors, but the wiring diagram shows that all four sensors have the same positive. With the engine running cold and codes clear (or not) I have 14V between the downstream sensor heater circuit wires, but can not light a test light across them with the sensor unplugged. I can light a test light between the hot wire and the frame. One of the upstream sensors seems to be working correctly - it has voltage AND will light a test light (I only tested one). To me, this confirms the fuse is good. PCM: These are ground switched circuits, and at the pins leading to the 4 sensors, I find no continuity to ground when the key is off, and find continuity when the key is turned to on, or the engine is running. However, the ground is not switched off on any of the 4 sensors after I idle for 10 minutes, and not after I take a test drive up a hill. This doesn't seem right. Are the heaters always running and burning out the sensors? Removing sensors: If I understand this, you are saying the sensors may use up the available current, preventing the light from running. I have tested by stripping wires on the old damaged sensor (it has no continuity across the heater circuit) and plugging it into the downstream sockets, then turned on the engine (codes clear, engine cold), and by putting probes into the empty socket. All the same result - 14V, but can't light a test light.
@@michaelscheu672 Gee, that sounds a lot like your driver is not working. To verify that you might backprobe the ground wire right at the PCM to exclude a broken wire between it and the sensor. Just remember that when testing ground wires that enter the PCM you want to use low current test lights so you don't expose the ground circuit inside the computer to excessive current. The cost for a replacement PCM would be high enough to justify a professional opinion, and if the driver is fried you'd need somebody to reflash a replacement PCM. Regarding your question about heaters, old vehicles do run that heater continuously. New vehicles use a PWM output that varies depending on temperature, etc. You may get more clues from a scan tool with live data. For example new sensors have a data pid for current flow in the heater circuit, and many have a bias voltage on top of the signal to expose details regarding circuit integrity.
Hey, thanks for stopping by. It's always nice to get a visit from an experienced pro. As you know I'm working through your channel videos, there is a wealth of experience there.
Great video, very well done and informative! Thank you! Any chance you have a suggestion on how to safely perform a drive cycle out on the road? My 2000 Silverado 1500 5.3L produced a not ready to test result upon attempt for emissions test.
Part of the drive cycle involves temperatures that are high enough to accurately test the evap system. At this time of year It won't complete if it is too cold, if the tank is too full or too empty, and if you haven't taken it for a long drive at highway speeds.
We have an '03 Avalanche with a 5.3. Engine surges during initial start up. It clears up once the engine temp comes up (less than 2 minutes). We got a P0135 Bank 1 Sensor 1 code. The old B1S1 sensor showed no power to the heater, the new sensor showed ok. Installed the new sensor, cleared the code. Within the first few miles engine light came back on. P0135 again. Checked the new sensor again, heater is getting power and is grounded. Checked the heater wires going up towards wherever it goes, key-on shows one wire has 12v battery voltage, the other shows its grounded. Just for the heck of it checked both fuses in the fuse box, both terminals on each fuse. Both have power (key-on). Cleared the code and disconnected the battery, engine light came back on the next day. P0135. Kind of stuck right now. I thought maybe it could be the engine temp sensor not working properly giving a wrong temp reading. Is that possible even if the surging clears up within a couple minutes? The surging only happens during cold start-up. Thanks.
Interesting problem. There's a chance your new sensor is not playing nice with your car. Is it OEM? Check the connector and make sure it didn't slip out, and check the wires to be sure you didn't melt a new wire on the cat. If not OEM, I'd consider swapping it for another sensor on the other side, and see if the problem migrates with the sensor or if it stays in B1S1. If it migrates with the sensor, you need another one, probably OEM. You might want to check for high resistance somewhere along that wire going to the computer. There are many ways to do that, some guys use a headlight bulb in series to see if it glows brightly when turned on, or you could probe either side of the heater wires with your multimeter and backprobe needles to see if all the voltage drop happens across the heater (which it should). If not you've got another area of resistance in your wiring, somewhere. The second thing I'd do is find a scan tool with live data and see if you get any clues there. On the OBD2 side you can get to that page I showed in the video, you want to see if the time to warm up is reduced in the sensor you're working on. Also you'll get more info regarding the cold warmup issue, coolant temp, idle control valve stepper motor counts, etc. Often high idle when cold is from some kind of vacuum leak, where you get a lean situation that improves when you snap the throttle. With this cold weather we're having, engine surge at startup is par for the course here in Canada, ha ha.
@@spelunkerd Thanks for responding. I forgot to mention we got 4 sensors from eBay (new) even though I only changed B1S1. After all the above was done, we changed the other 3 sensors, cleared the code, engine light came back on, and it still came up P0135. Checked the new B1S1 again and the heater side isn't shorted, there's power and ground coming from up side, ground is good, and the fuses haven't blown. Starting to suspect there's a short or break in the wire between the fuse box and the computer? If that's where it is we probably won't touch it. The surging only happens for the first couple minutes during cold start up (cold meaning 65 degrees or above). Previously we had a P0171 and P0174 lean codes both banks. But we traced it down. Haven't had any lean codes since. Appreciate your time Thank You. 👍
Question : After you replaced it , you gathered the new data with COLD engine , correct ? If engine is HOT, it won't activate the heater . By the way , great video, thanks for the details .
Yes, it was cold. In this old vehicle, to be honest I don't think it matters. Like PWM control, ability to turn off sensor heaters was a later design change to save energy and eke a tiny fuel economy benefit. It's surprising how much energy is wasted even in electric vehicles, most of which ends up as heat.
The two thicker heater wires that are often the same color are pretty simple, one side will be ground and the other side will be 12V, sometimes with a PWM intermittent pattern in newer cars. The sensor wires are more tricky, especially if you've got a newer wide band style sensor. One side will be ground, and often the other side will have a bias voltage applied by the computer to allow it to make conclusions about circuit integrity. To know what that bias voltage is, and to know what to expect on the sensor wires, your best resource is the dealer service manual. Older style narrow band sensors like these are pretty simple. The other variable is the way once a modern computer detects a problem, it may shut down output to that sensor to prevent damage to sensitive electronics. You may need to erase codes to allow the computer to try again to get a newly installed sensor to work properly.
Autel 906BT. Having gone through many scan tools, it's the best scan tool I've had yet. Only problem is the expense of subscription updates, I couldn't afford them so I let the updates expire. It's great to have a scan tool with some bidirectional control, even though it can't do real programming or reflashing. Thanks for stopping by, Ben!
One big thing that I suggest is always making sure to use genuine oem sensors. It may be a little pricey but will definitely be worth it in the long run
i need your help, I have the same o2 connector as in your video, 4 wire, 2x whites for elements and black/gray for signal. I been getting 0141 and 0138 which points to the downstream o2, and i replaced it and still getting hi volts b1s2. i checked the voltage on the truck side, as in your video, and im getting 13v for the elements and 4v for the signal. my upstream sensor is working fine and no other CEL codes have returned its always 0138 and/or 0141
The P-0138 is the interesting one, suggesting that somehow high voltage is leaking into the sensor side of the circuit. I'd be wondering if there is a short to voltage somewhere along the path of the wires. I've seen that before, and as I recall ScannerDanner did a video on that intriguing diagnosis. If you have a scan tool that will show live data, you can view the data coming back to the computer. You can even apply a ground to the signal wire and see if the signal drops. I would not apply power to the signal wire except through a big resistance so the PCM can't be damaged. There's a famous trick where the mechanic touches a 12V source with one hand, and with a wet finger of the other hand touches the signal wire. Even that tiny power through the human body is enough to shift the result on the scan tool, verifying wire integrity. In your case you need to inspect the wiring harness looking for a short from the live heater wire to your sensor wire. Pay close attention to connectors, wires that got too close to exhaust, sharp edges, etc. To rule out the new sensor as a cause, disconnect it and see if the live data in the scan tool shows a drop in voltage. The scan tool won't necessarily show 12V, there are internal zener diodes inside the PCM that drop the voltage down to the safe 0-1 V range. If everything still checks out, remember to erase codes and try again. If you don't have a scan tool to erase codes, disconnect the neg pole of the battery for a minute and try again. The PCM has a protective mechanism with some codes to stop looking at sensor data if the voltage coming back is possibly dangerous.
First of great video. I'm having a o2 sensor heater problem and all of these videos are the same in looking for a video that explains why the ground of the o2 sensor falls off when I connect the sensor or the text light bulb. Ohh I traced the ground wire all the way to the ecm and I tested the wire close to the ecm to make sure there was no breaks on the way. What you think?? I'm thinking bad ecm
Inside the ECM you may have more sophisticated hardware that limits current, so it may be wise to test each component individually. ScannerDanner posted an example of that in a video today, explaining why his test light was failing to pick up the on/off signal from the ECM for a shift solenoid. If in doubt you need to simplify by dividing the circuit, to be sure you're condemning the correct part. Be sure when testing the driver not to apply 12V without limiting current somehow, since high current test devices may cause secondary downstream problems in the ECM. Many guys reserve an LED test light for this situation, where it can come on yet send minimal downstream current into the driver. With two grounds on an old style typical oxygen sensor, you need to be sure the high current from the heater doesn't get accidentally routed through the sensor ground, where it can mess up the sensitive components that monitor that circuit. Occasionally weird things can happen, where for example the ECM may protect itself by turning off driver service to a device that is sending dangerous current. In that unusual situation you need to clear the codes first before the driver is willing to talk to downstream devices. Good luck!
@@spelunkerd thanks for getting back. I'm saying without the o2 connected I'm getting 12v from the heater wires but when I plug the o2 or the text like the voltage leave when I remove the voltage come back. I no ecm rarely goes out I'm just thinking thats the only thing thats left. I have tried 3 o2 sensor one of them being one GM 2009 impala.
@@rodneywilliams4565 I'm having a little trouble visualizing what you are saying. Most heaters are ground side switched, by the PCM. So for a ground side switched heater, you'll get 12V on the return side when no ground is supplied, which should drop to zero when the pcm offers a ground. All the voltage drop happens across the main resistance, the heater. On the voltage side, you'll have 12V, on or off. Voltage side switching is opposite of that, easy to understand by looking at the wiring diagram. If confused, be sure you're looking at wiring diagrams for your vehicle. You could test another O2 sensor circuit in the car to better understand what should be normal.
I revisited your video. I noticed a bit of conflict , maybe your vidoe pieces are out of order . At 8:27 the sensor is loose, turning freely; however, following that you are using 2 keys and other ticks to losen it up .
A common technique is to back it out until you meet resistance, spray with penetrating oil, tighten it back up, spray again, then loosen again. You go back and forth rather than giving it all on one pass. This is because carbon deposits on the sensor inside the exhaust meet the threads and can damage the threads as you back out. In some situations you can remove a bolt only to find all the threads from the female side have come off. Bolts and sensors can break, too. If that happens, you first drill it out, then you are faced with options of retapping threads, putting in a helicoil, or cutting off the bung and welding on a new bung. All that takes time so it is wise to have patience in an effort to avoid problems later. In this case I found resistance was increasing so I did that. Thanks for your input, most people would not have noticed.
Curious for your opinion, I had some rats chew through the o2 sensor wiring of the sensor not the car harness at least. but after repair i am still getting a check engine light for the heater circuit. I soldered in the repair wires, but the wiring I used was 18 gauge where the original is probably 14 ish. Do you think this 6 inch repair section of smaller guage wire could really cause enough resistance to trigger the CEL in that heater circuit ? @spelunkerd
Good question, probably not, but more modern vehicles with Air/Fuel ratio sensors are more sensitive to subtle differences in resistance. Those more modern vehicles have data pids that show differences on a scan tool, if you can get your hands on one that offers live data. Even aftermarket O2 sensors may not play nice with your car's computer. I'd be concerned that a short might have damaged the driver. Work it up in the usual way, check for power and ground on each side, and put some kind of light bulb into the circuit in place of the O2 sensor to see if the light turns on when engine is cold. Good luck!
Hi , so i am getting bank 1, sensor 1 &2 both low heater circuit. Should i be getting constant 12v when i check the 12v circuit? When i check mine, test light is bright then flash 2 times then doesn’t light anymore. I am trying to figure out if its pulses or should be constant 12v on heater circuit. 2005 Dodge Dakota w/4.7L engine. Would appreciate any input. Thanks
Many newer vehicles use a Pulse Wave Modulated signal to power the heaters, delivering 12V with a picket fence style of delivery. It could flash, although I'd expect it to be regular and consistent. Remember to test the engine cold since if the cats are already warmed up the heaters may dial themselves down, usually reducing frequency if the signal is PWM. The other confusing thing is the way the PCM might turn itself off if the circuit is shorted, in an effort to protect the internal driver from overheating. I'd look for a more simple way to make the diagnosis, such as with an ohmeter on the sensor heater itself. If you prove the sensor(s) are bad, replace them, erase codes, and watch to see the signal recover.
Thanks for the response. Both my oxygen sensors that the codes are showing up for are brand new. I installed them. Denso brand. I will check the both heater’s continuity but i am assuming the are good because they are both brand new. I checked the ground circuit and both are ok….
@@zeppone4045 Gee, I hope the driver is still OK. The way you get a couple of flashes, then nothing is worrisome, almost as though the computer is looking for the correct resistance and not finding it, then shutting the circuit down. Sometimes if there is still a code in the computer, you need to erase that code first before the PCM will allow a retry. I think I'd start by tracing that circuit all the way back to the fuse and the computer, looking for a dead short somewhere. Especially around the heat of the cat, you could have melted insulation causing a dead short. To examine that circuit properly you may want to remove the connector at the PCM, then look for a short either with your ohmeter or with active testing using a test light. Good luck!
Thanks for the info. Yes i am going disconnect connectors at PCM and check for continuity and shorts in the oxygen sensor circuits. I also might install a 12v light bulb 💡 onto heater circuit and see how it reacts when i test again after clearing codes…
The biggest challenge is to distinguish cause from effect, ie whether abnormal readings are accurate, reflecting something wrong upstream in the fuel trim or whether the readings themselves are spurious because the sensor is poorly made or damaged. The best way to do that is with a scan tool, but even then with air/fuel sensors it can be tricky. On the scan tool you want to show the sensor readings vary between 0.1 V and 0.9V, and if you introduce air into the intake the voltage drops, if you introduce propane it increases. Snap throttle to see if the cycling frequency rises and see if the readings go rich (0.9V). You can also apply voltage through a resistor, even your own body, and see if the computer detects the change. I would avoid the confusion of buying aftermarket sensors, the risk of time wasting confusion is not worth it. Scannerdanner did a whole series of videos describing how this is done.
@@spelunkerd thank you for all of the information I appreciate I went back and read the reviews on the cheap 02 sensors everyone basically said the same thing they failed so I am just going to stick with the AC Delco and see if that's it, and I'll run the voltage test too. So when I blip the throttle I should get the 9v reading or is it the opposite? Just want to make sure I run it right.
@@aheis1313 Assuming you have narrow band sensors rather than the new wide band air fuel sensors, here's a quick summary. When you stomp on the throttle the engine is designed to run rich, which will push the upstream sensors to spike at a maximum of about 0.9V. Then when you release the throttle the sensors will shift lean, dropping to about 0.1V. So the easy way to assess how the upstream sensors swing is to bring up a live data graph on your scan tool, sit in the car and stomp on the throttle. At fast rpm you should also see more rapid swinging of upstream sensors between rich and lean, and a lazy sensor may not keep up with the other sensor on the opposite bank. That's also a useful trick to investigate lean trouble codes. A vacuum leak will instantly improve when you snap the throttle, whereas a bad MAF or bad fuel delivery will worsen at snap throttle.
I haven't yet found a scan tool that I didn't learn to hate. Some guys say nice things about the Launch. I would not recommend Autoenginuity, it has too many bugs. Autel is pretty good but subscription fees are outrageous if you want to stay up to date. I've always wanted to try a used SnapOn scan tool, you might find one on ebay for cheap. There are some really cheap tools that can run off a phone that might be worth a try. All big scan tool companies have many versions, with a huge price range, but for starting out all you need is a code reader and something that offers live data.
i tested 3 sensors and all have about 3 ohm resistance, but all heat up too slow , i tested wires , i installed 12v bulb and it blinks when i turn key for contact and when engine is started, any idea?
With engine on at cold startup you should get either a continuous glow of that bulb or repetitive high frequency flashing. Some computers will turn off the heater circuit if the circuit is shorted to ground or has a trouble code, so you might try writing down and then erasing the code, then try again. Aftermarket sensors may not behave the way the computer expects so that may be an issue.
I have barometric pressure too low (P0129) and all four 02 sensor heater circuit high codes. Anyone have any idea what could be wrong? Also barometric pressure light turns on without starting vehicle
I'll throw out a guess those two are unrelated. Don't forget the easy fix, the fuse for the heater circuit which would take out all four at once. Hopefully the PCM driver itself is OK. Once fixed, you may need to erase codes for the PCM to give it another try. It's not uncommon for barometric pressure gauges to go bad. I'd seek out the sensor in question, check power and ground to the device. Check alldata to find your vehicle and see manufacturer details that will guide further testing. This might be one of those devices that sends a variable voltage to the PCM. If so, to evaluate the sensor wire you can apply a tiny voltage complete with current limiting resistance by using the diode function on your multimeter, then look at a scan tool for change in value to verify circuit and PCM continuity. Never test the PCM with external voltage and no resistance because you could fry the PCM. if all is well, change the sensor.
Good question, I'm surprised nobody asked that before. There is very little effect on the car except the pesky check engine light on the dash, especially for oxygen sensors that are downstream of the cat. Environmental protection laws are built into the algorithms, which is why they demand a trouble light. Without the heater, the car will go into closed loop a couple of minutes slower, increasing emissions at first start. I'm told Chrysler does use the downstream sensor 2 data to adjust fuel trim, but most other manufacturers use the downstream sensors purely to assess how well the catalytic converter is working. The upstream sensors are more critical, and I wouldn't hesitate to change those because you'll get brisk return on your dollar by improving fuel economy. Newer broad band oxygen sensors require a much hotter sensor to work properly, so the heater is more critical for those.
@@spelunkerd My Tahoe's getting a po135 bank 1 sensor 1 code heater malfunction so if i just leave it be and clear the light whenever it comes on it wont affect engine performance? Im just trying get an idea on how these work but id probably be better off just replacing it
@@roltyd22 Sensor 1 is upstream of the cat, so it is used for engine performance, but it likely starts working within a few minutes from the generated heat of the cat anyway. So, it's not urgent, you could leave it. But that light will be annoying, and if other problems arise you may not know it because the light is already on. And if you want to sell the vehicle, resale value is dramatically less if the light is on. As I showed, replacing the sensor is pretty easy, and if you don't have the right tools a mechanic could do it easily. So for all those reasons it is probably best to bite the bullet and replace it. Also old sensors get 'lazy', which does affect fuel economy.
good video but my problem I got check engine with p0130 p0135 p0141 p0155 p0161 p0136 codes all at once I don't even know where the problem might come from.
Scroll to 7:52, it's written in the video for this vehicle and this sensor, (3.5-14 ohms). My new sensor was out of spec at 15.1 ohms. Every vehicle is a little different so if you have a different make and model, expect some variance. For dealers specs I use alldatadiy, although their long term subscription fees have escalated quickly.
You should have run a tap in that hole. You should be able to screw those in with your fingers. Unless GM has changed the type of the O2 sensors they used when I worked on them, I would say the new looks like it is not a OEM part. I retired from working at a GM dealer in 2002, so I could be wrong. But the one you removed looks OEM for sure. Unless you got that from a GM dealer, I would question it being real. There are a lot of parts online claiming to be OEM, but they are not. Most aftermarket electrical parts almost never worked properly.
Those are good points! I did get the part at the local dealer, but even so GM have outsourced their parts so you never know. It's working fine, and for a downstream sensor it should be fine. I do have a thread chaser set so the only thing holding me off using it was laziness. In the end it spun on fine. Thanks for stopping by!
In older vehicles the data from sensors placed downstream of the cat are there almost entirely to assess the function of the cat. So, even if unplugged there should be little effect on fuel mileage or fuel balance. The PCM will trigger an unavoidable check engine light and trouble code. The vehicle will fail emissions testing if you live in an area demanding it pass, but the vehicle should drive fine.
@@bubbaclaypoole7579 With no cat at all I'd be surprised if any extender would be long enough to flatten the rich/lean curve. It seems like a lot of work when you could simply apply black tape over the light on the dash.
@@bubbaclaypoole7579 A simple resistor works for air bag circuits and even some first gen security circuits, and there is some internal resistance to the signal part of an O2 sensor. But recall that O2 sensors actually produce voltage and tiny current after they warm up, much like a battery within a narrow range which the PCM is looking for. When the cat is working properly the normal wide swings of voltage are flattened out within a specific range. Some circuits also have a bias voltage used by the PCM to look for opens and shorts. It would be tricky to try and mimic a normal O2 sensor closely enough that the PCM is not able to detect a problem. You also have two sides to the circuit, with a heater side that needs to be approximately right as well. For the amount of fiddling it would take to try and get it right, I'd just live with the dash light.
That's never happened in my old '98 Dodge but in about 2002 Chrysler moved to an ASD relay inside the TIPM, which was problematic because of corrosion. Through the next decade TIPM corrosion and various issues became notorious.
If it's the identical sensor again, then possibly the aftermarket sensor is not recognized as correct for your car. Aftermarket sensors are a lot cheaper but don't always play nice with the OEM equipment. Alternatively if it is the identical trouble code then possibly you've got a problem with wiring or the connector. Work it up as shown in the video and you'll likely sort it out.
@@spelunkerd thanks for the answer i bought that sensor for 12k pesos here in the philippines and they said its an original i hope it just the wiring like the seller said when i return to him
Although I understand your point, remember that this is the part I'm throwing away. The new sensor comes with that length of wire up to the connector. Were I not to throw away that wire, it is easy enough to fix with liquid tape. Professionals puncture wires every day, and if repaired correctly there is no issue even if they continue to use that wire. There are of course alternate approaches. I have a $400 set of breakout T connections that require front probing with correct size taps. When the wrong size is chosen, corrosion or loosened connections can start there. And of course there's the old inexpensive standby of backprobing with a fine needle, again vulnerable to eventual water ingress when you slide that needle along the rubber seal. So, various options, all carry some risk. Remember that if you're trying to measure response with a scan tool, or if you're doing simple drop testing, you need the connector be fully hooked up to assess response. Even front probing one side of the connector carries risk. I remember ScannerDanner rolling his eyes at remarks like this. What method would you use? Or, do you play the parts swapping game and forget accurate diagnosis?
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Engine light!? GET ME THE CANNON!!! Oh wait... We'll diagnose it the right way 👍 Great job sir! Glad to see the power probe in action 👊
Outstanding presentation. Scannerdanner would be proud. Eric O is a class act for sure. A few of us gained a new tool from his generosity. Great job!
Scannerdanner is an expert but I don't consider him the best teacher.
Your methodology is sound. Logic is followed. Reason in employed. I learned much. Thank you for sharing.
I just gotta say, wonderful way of producing this video more than anything, very well explained and great info and overall great production.
Holy AMAZING! You are so thorough and helpful with your teachings, thank you so much for taking the time to share and help others! You have a true gift!
Such a thorough presentation of an Oxygen O2) Sensor, Heated and Excellent diagnosis in Briefing Detailing. Thank You for Simplified Version!
Nice job with the diagnosis. Getting that old O2 out can be a struggle so it sure is good to be confident a new sensor will fix the problem. Makes the struggle worthwhile!
The wait for the next video is always worth it.
great share Dave , I sure have seen folks throw parts at a rig hoping to fix it ! This should help some of them out .. ENJOYED
I rarely comment on youtube videos, but like other comments, I wants very impressed. Thorough and detailed. Thank you!
Your dogs stole the show, so cute.
Didn't know you had a channel. Love your demeanor and organization.
August, thanks for stopping by! As you know I've been following your arborist channel. Professionals like yourself show us how much better TH-cam videos can be, you raise the bar. I live in Victoria, BC, but have had a few occasions to visit your amazing Oregon.
@@spelunkerd You’re welcome. I’ll be waiting for a new vids 💪🏼
Great work Dave and nice presentation of the steps to fix the problem! Have a great day!
Thanks for stopping by, Terry!
Great video, that really helps me understand how this system works. Yet, I am still struggling to fix my O2 sensor problem. I have code P0161 (B2S2 heater circuit malfunction) on a 2001 Tundra 4.7L engine. I found a deal on an aftermarket L/R pair, so naively bought these and replaced both sides. After resetting the code, the check engine light came back on within 10 miles with the same code. So now I tested the resistance in the sensors I pulled and the ones on the vehicle:
B1S2 15 ohms - Original OEM part
B2S2 0 ohms - Original OEM part
B1S2 11 ohms - Installed aftermarket part
B2S2 0 ohms - Installed aftermarket part
B1S1 16 ohms - OEM part
B2S1 10.7 Ohms-Aftermarket part installed by previous owner
I read this to say that the original B2S2 was indeed bad, that the new B2S2 is bad, and that the aftermarket parts I installed may have the wrong specs. I did not test them new. Also, the B2S1 may be failing.
Could the wrong specs on the aftermarket part explain the apparent failure of the new part? If so wouldn't both go bad? Could there be something upstream causing the failure?
Next, I tested voltage at the harnesses running a cold engine and sensor wires disconnected:
B1S2 14V, but will not light a test light at the harness
B2S2 14V, but will not light a test light at the harness
B2S1 14V, WILL light a test light at the harness
In all three of these, the test light does light up if I connect positive at the harness to the frame, showing the 'problem' is in the switched neutral. Does this mean there is wire damage? Or the ECU is malfunctioning? Or something else?
With such low resistance, the risk of high current damaging downstream parts is significant, so many PCM grounded circuits will shut down that function if resistance in the circuit is too low. In that situation you may need to erase the trouble codes before the circuit will work properly. I would buy one OEM sensor from the dealer, erase the codes before firing the truck back up, then see what happens. If it works, you could go ahead and buy the rest. An alternate possibility is that the driver (or ground wire to the PCM module) is fried, but I wouldn't jump to that conclusion yet.
@@spelunkerd Thanks for the quick response. I did figure out that the PCM shuts down the circuit, and tested it after clearing codes, but still haven't been able to get it to light a test light. The check engine light comes back on pretty fast. I have a sensor on order, and will repost when I get it installed.
@@michaelscheu672 That's concerning. You could check the fuse, and check the power and ground sources, perhaps even tracing it all the way back to the pcm to build evidence for a wiring problem along the way. Let's hope the PCM grounding driver isn't fried. Some of these produce a PWM square wave output, more prominent when the engine is cold, so I'd be testing with engine cold and codes erased. If your oxygen sensor has very low voltage, remove it before testing so that your test light won't be bypassed through a parallel low resistance arm.
@@spelunkerd Still waiting on the part, but in the meantime:
The Fuse: I can't figure out which fuse controls the positive side of the sensors, but the wiring diagram shows that all four sensors have the same positive. With the engine running cold and codes clear (or not) I have 14V between the downstream sensor heater circuit wires, but can not light a test light across them with the sensor unplugged. I can light a test light between the hot wire and the frame. One of the upstream sensors seems to be working correctly - it has voltage AND will light a test light (I only tested one). To me, this confirms the fuse is good.
PCM: These are ground switched circuits, and at the pins leading to the 4 sensors, I find no continuity to ground when the key is off, and find continuity when the key is turned to on, or the engine is running. However, the ground is not switched off on any of the 4 sensors after I idle for 10 minutes, and not after I take a test drive up a hill. This doesn't seem right. Are the heaters always running and burning out the sensors?
Removing sensors: If I understand this, you are saying the sensors may use up the available current, preventing the light from running. I have tested by stripping wires on the old damaged sensor (it has no continuity across the heater circuit) and plugging it into the downstream sockets, then turned on the engine (codes clear, engine cold), and by putting probes into the empty socket. All the same result - 14V, but can't light a test light.
@@michaelscheu672 Gee, that sounds a lot like your driver is not working. To verify that you might backprobe the ground wire right at the PCM to exclude a broken wire between it and the sensor. Just remember that when testing ground wires that enter the PCM you want to use low current test lights so you don't expose the ground circuit inside the computer to excessive current. The cost for a replacement PCM would be high enough to justify a professional opinion, and if the driver is fried you'd need somebody to reflash a replacement PCM. Regarding your question about heaters, old vehicles do run that heater continuously. New vehicles use a PWM output that varies depending on temperature, etc. You may get more clues from a scan tool with live data. For example new sensors have a data pid for current flow in the heater circuit, and many have a bias voltage on top of the signal to expose details regarding circuit integrity.
Excellent!
nice organized delivery of info 💪🏽
Good explanation and nice effective testing nice job sir
Dang! I’ve been looking for this video forever thank you so much for posting!
Brilliant.
great video
GREAT VIDEO AND WELL EXPLAINED , Glad to find your channel .
Hey, thanks for stopping by. It's always nice to get a visit from an experienced pro. As you know I'm working through your channel videos, there is a wealth of experience there.
Nice Job glad to see another video. I hope all is well and you are safe and healthy my friend. Here is to 2021, Thanks for sharing.
Great job! Thanks!
How do you only have 1200 likes? This is very informative. Job well done 👍
Awesome video content 😊 thanks for sharing 🙏 looking forward for more amazing video 👍 all the best and see you my friend ❤
Hi nice info and video i have 2004 silverado and i got a pending code p1035 it says 02 heater circuit is this the same as your problem
Another great video. Thanks for sharing it.
Thanks for watching!
Great video, very well done and informative! Thank you! Any chance you have a suggestion on how to safely perform a drive cycle out on the road? My 2000 Silverado 1500 5.3L produced a not ready to test result upon attempt for emissions test.
Part of the drive cycle involves temperatures that are high enough to accurately test the evap system. At this time of year It won't complete if it is too cold, if the tank is too full or too empty, and if you haven't taken it for a long drive at highway speeds.
Very Well DONE... ;0)
Eric-O is the goat
It may not be necessary to have scanners and probes but it sure makes it fun. Lol
We have an '03 Avalanche with a 5.3. Engine surges during initial start up. It clears up once the engine temp comes up (less than 2 minutes). We got a P0135 Bank 1 Sensor 1 code. The old B1S1 sensor showed no power to the heater, the new sensor showed ok. Installed the new sensor, cleared the code. Within the first few miles engine light came back on. P0135 again. Checked the new sensor again, heater is getting power and is grounded. Checked the heater wires going up towards wherever it goes, key-on shows one wire has 12v battery voltage, the other shows its grounded. Just for the heck of it checked both fuses in the fuse box, both terminals on each fuse. Both have power (key-on). Cleared the code and disconnected the battery, engine light came back on the next day. P0135. Kind of stuck right now. I thought maybe it could be the engine temp sensor not working properly giving a wrong temp reading. Is that possible even if the surging clears up within a couple minutes? The surging only happens during cold start-up. Thanks.
Interesting problem. There's a chance your new sensor is not playing nice with your car. Is it OEM? Check the connector and make sure it didn't slip out, and check the wires to be sure you didn't melt a new wire on the cat. If not OEM, I'd consider swapping it for another sensor on the other side, and see if the problem migrates with the sensor or if it stays in B1S1. If it migrates with the sensor, you need another one, probably OEM. You might want to check for high resistance somewhere along that wire going to the computer. There are many ways to do that, some guys use a headlight bulb in series to see if it glows brightly when turned on, or you could probe either side of the heater wires with your multimeter and backprobe needles to see if all the voltage drop happens across the heater (which it should). If not you've got another area of resistance in your wiring, somewhere. The second thing I'd do is find a scan tool with live data and see if you get any clues there. On the OBD2 side you can get to that page I showed in the video, you want to see if the time to warm up is reduced in the sensor you're working on. Also you'll get more info regarding the cold warmup issue, coolant temp, idle control valve stepper motor counts, etc. Often high idle when cold is from some kind of vacuum leak, where you get a lean situation that improves when you snap the throttle. With this cold weather we're having, engine surge at startup is par for the course here in Canada, ha ha.
@@spelunkerd Thanks for responding. I forgot to mention we got 4 sensors from eBay (new) even though I only changed B1S1. After all the above was done, we changed the other 3 sensors, cleared the code, engine light came back on, and it still came up P0135. Checked the new B1S1 again and the heater side isn't shorted, there's power and ground coming from up side, ground is good, and the fuses haven't blown. Starting to suspect there's a short or break in the wire between the fuse box and the computer? If that's where it is we probably won't touch it. The surging only happens for the first couple minutes during cold start up (cold meaning 65 degrees or above). Previously we had a P0171 and P0174 lean codes both banks. But we traced it down. Haven't had any lean codes since. Appreciate your time Thank You. 👍
Question : After you replaced it , you gathered the new data with COLD engine , correct ? If engine is HOT, it won't activate the heater . By the way , great video, thanks for the details .
Yes, it was cold. In this old vehicle, to be honest I don't think it matters. Like PWM control, ability to turn off sensor heaters was a later design change to save energy and eke a tiny fuel economy benefit. It's surprising how much energy is wasted even in electric vehicles, most of which ends up as heat.
@@spelunkerd Makes sense.
What is the voltage that your power probe should register on each of the pins on the harness side of the O2 sensor plug?
The two thicker heater wires that are often the same color are pretty simple, one side will be ground and the other side will be 12V, sometimes with a PWM intermittent pattern in newer cars. The sensor wires are more tricky, especially if you've got a newer wide band style sensor. One side will be ground, and often the other side will have a bias voltage applied by the computer to allow it to make conclusions about circuit integrity. To know what that bias voltage is, and to know what to expect on the sensor wires, your best resource is the dealer service manual. Older style narrow band sensors like these are pretty simple. The other variable is the way once a modern computer detects a problem, it may shut down output to that sensor to prevent damage to sensitive electronics. You may need to erase codes to allow the computer to try again to get a newly installed sensor to work properly.
Excellent video. What is the make and model of your scan tool?
Autel 906BT. Having gone through many scan tools, it's the best scan tool I've had yet. Only problem is the expense of subscription updates, I couldn't afford them so I let the updates expire. It's great to have a scan tool with some bidirectional control, even though it can't do real programming or reflashing. Thanks for stopping by, Ben!
I am a professional technician for 40 years. People see you do it, they will do it too.
My blazer keeps throwing a 02 sensor code, even after I replace it with a new one.
One big thing that I suggest is always making sure to use genuine oem sensors. It may be a little pricey but will definitely be worth it in the long run
Did you reset the computer?
i need your help, I have the same o2 connector as in your video, 4 wire, 2x whites for elements and black/gray for signal. I been getting 0141 and 0138 which points to the downstream o2, and i replaced it and still getting hi volts b1s2. i checked the voltage on the truck side, as in your video, and im getting 13v for the elements and 4v for the signal. my upstream sensor is working fine and no other CEL codes have returned its always 0138 and/or 0141
The P-0138 is the interesting one, suggesting that somehow high voltage is leaking into the sensor side of the circuit. I'd be wondering if there is a short to voltage somewhere along the path of the wires. I've seen that before, and as I recall ScannerDanner did a video on that intriguing diagnosis. If you have a scan tool that will show live data, you can view the data coming back to the computer. You can even apply a ground to the signal wire and see if the signal drops. I would not apply power to the signal wire except through a big resistance so the PCM can't be damaged. There's a famous trick where the mechanic touches a 12V source with one hand, and with a wet finger of the other hand touches the signal wire. Even that tiny power through the human body is enough to shift the result on the scan tool, verifying wire integrity. In your case you need to inspect the wiring harness looking for a short from the live heater wire to your sensor wire. Pay close attention to connectors, wires that got too close to exhaust, sharp edges, etc. To rule out the new sensor as a cause, disconnect it and see if the live data in the scan tool shows a drop in voltage. The scan tool won't necessarily show 12V, there are internal zener diodes inside the PCM that drop the voltage down to the safe 0-1 V range. If everything still checks out, remember to erase codes and try again. If you don't have a scan tool to erase codes, disconnect the neg pole of the battery for a minute and try again. The PCM has a protective mechanism with some codes to stop looking at sensor data if the voltage coming back is possibly dangerous.
First of great video. I'm having a o2 sensor heater problem and all of these videos are the same in looking for a video that explains why the ground of the o2 sensor falls off when I connect the sensor or the text light bulb. Ohh I traced the ground wire all the way to the ecm and I tested the wire close to the ecm to make sure there was no breaks on the way. What you think?? I'm thinking bad ecm
Inside the ECM you may have more sophisticated hardware that limits current, so it may be wise to test each component individually. ScannerDanner posted an example of that in a video today, explaining why his test light was failing to pick up the on/off signal from the ECM for a shift solenoid. If in doubt you need to simplify by dividing the circuit, to be sure you're condemning the correct part. Be sure when testing the driver not to apply 12V without limiting current somehow, since high current test devices may cause secondary downstream problems in the ECM. Many guys reserve an LED test light for this situation, where it can come on yet send minimal downstream current into the driver. With two grounds on an old style typical oxygen sensor, you need to be sure the high current from the heater doesn't get accidentally routed through the sensor ground, where it can mess up the sensitive components that monitor that circuit. Occasionally weird things can happen, where for example the ECM may protect itself by turning off driver service to a device that is sending dangerous current. In that unusual situation you need to clear the codes first before the driver is willing to talk to downstream devices. Good luck!
@@spelunkerd thanks for getting back. I'm saying without the o2 connected I'm getting 12v from the heater wires but when I plug the o2 or the text like the voltage leave when I remove the voltage come back. I no ecm rarely goes out I'm just thinking thats the only thing thats left. I have tried 3 o2 sensor one of them being one GM 2009 impala.
@@rodneywilliams4565 I'm having a little trouble visualizing what you are saying. Most heaters are ground side switched, by the PCM. So for a ground side switched heater, you'll get 12V on the return side when no ground is supplied, which should drop to zero when the pcm offers a ground. All the voltage drop happens across the main resistance, the heater. On the voltage side, you'll have 12V, on or off. Voltage side switching is opposite of that, easy to understand by looking at the wiring diagram. If confused, be sure you're looking at wiring diagrams for your vehicle. You could test another O2 sensor circuit in the car to better understand what should be normal.
I revisited your video. I noticed a bit of conflict , maybe your vidoe pieces are out of order . At 8:27 the sensor is loose, turning freely; however, following that you are using 2 keys and other ticks to losen it up .
A common technique is to back it out until you meet resistance, spray with penetrating oil, tighten it back up, spray again, then loosen again. You go back and forth rather than giving it all on one pass. This is because carbon deposits on the sensor inside the exhaust meet the threads and can damage the threads as you back out. In some situations you can remove a bolt only to find all the threads from the female side have come off. Bolts and sensors can break, too. If that happens, you first drill it out, then you are faced with options of retapping threads, putting in a helicoil, or cutting off the bung and welding on a new bung. All that takes time so it is wise to have patience in an effort to avoid problems later. In this case I found resistance was increasing so I did that. Thanks for your input, most people would not have noticed.
Curious for your opinion, I had some rats chew through the o2 sensor wiring of the sensor not the car harness at least. but after repair i am still getting a check engine light for the heater circuit. I soldered in the repair wires, but the wiring I used was 18 gauge where the original is probably 14 ish. Do you think this 6 inch repair section of smaller guage wire could really cause enough resistance to trigger the CEL in that heater circuit ? @spelunkerd
Good question, probably not, but more modern vehicles with Air/Fuel ratio sensors are more sensitive to subtle differences in resistance. Those more modern vehicles have data pids that show differences on a scan tool, if you can get your hands on one that offers live data. Even aftermarket O2 sensors may not play nice with your car's computer. I'd be concerned that a short might have damaged the driver. Work it up in the usual way, check for power and ground on each side, and put some kind of light bulb into the circuit in place of the O2 sensor to see if the light turns on when engine is cold. Good luck!
Hi , so i am getting bank 1, sensor 1 &2 both low heater circuit. Should i be getting constant 12v when i check the 12v circuit? When i check mine, test light is bright then flash 2 times then doesn’t light anymore. I am trying to figure out if its pulses or should be constant 12v on heater circuit. 2005 Dodge Dakota w/4.7L engine. Would appreciate any input. Thanks
Many newer vehicles use a Pulse Wave Modulated signal to power the heaters, delivering 12V with a picket fence style of delivery. It could flash, although I'd expect it to be regular and consistent. Remember to test the engine cold since if the cats are already warmed up the heaters may dial themselves down, usually reducing frequency if the signal is PWM. The other confusing thing is the way the PCM might turn itself off if the circuit is shorted, in an effort to protect the internal driver from overheating. I'd look for a more simple way to make the diagnosis, such as with an ohmeter on the sensor heater itself. If you prove the sensor(s) are bad, replace them, erase codes, and watch to see the signal recover.
Thanks for the response. Both my oxygen sensors that the codes are showing up for are brand new. I installed them. Denso brand. I will check the both heater’s continuity but i am assuming the are good because they are both brand new. I checked the ground circuit and both are ok….
@@zeppone4045 Gee, I hope the driver is still OK. The way you get a couple of flashes, then nothing is worrisome, almost as though the computer is looking for the correct resistance and not finding it, then shutting the circuit down. Sometimes if there is still a code in the computer, you need to erase that code first before the PCM will allow a retry. I think I'd start by tracing that circuit all the way back to the fuse and the computer, looking for a dead short somewhere. Especially around the heat of the cat, you could have melted insulation causing a dead short. To examine that circuit properly you may want to remove the connector at the PCM, then look for a short either with your ohmeter or with active testing using a test light. Good luck!
Thanks for the info. Yes i am going disconnect connectors at PCM and check for continuity and shorts in the oxygen sensor circuits. I also might install a 12v light bulb 💡 onto heater circuit and see how it reacts when i test again after clearing codes…
Ive got through 2 02 sensors and before i buy another, what should i look for on the connector side?
The biggest challenge is to distinguish cause from effect, ie whether abnormal readings are accurate, reflecting something wrong upstream in the fuel trim or whether the readings themselves are spurious because the sensor is poorly made or damaged. The best way to do that is with a scan tool, but even then with air/fuel sensors it can be tricky. On the scan tool you want to show the sensor readings vary between 0.1 V and 0.9V, and if you introduce air into the intake the voltage drops, if you introduce propane it increases. Snap throttle to see if the cycling frequency rises and see if the readings go rich (0.9V). You can also apply voltage through a resistor, even your own body, and see if the computer detects the change. I would avoid the confusion of buying aftermarket sensors, the risk of time wasting confusion is not worth it. Scannerdanner did a whole series of videos describing how this is done.
@@spelunkerd thank you for all of the information I appreciate I went back and read the reviews on the cheap 02 sensors everyone basically said the same thing they failed so I am just going to stick with the AC Delco and see if that's it, and I'll run the voltage test too. So when I blip the throttle I should get the 9v reading or is it the opposite? Just want to make sure I run it right.
@@aheis1313 Assuming you have narrow band sensors rather than the new wide band air fuel sensors, here's a quick summary. When you stomp on the throttle the engine is designed to run rich, which will push the upstream sensors to spike at a maximum of about 0.9V. Then when you release the throttle the sensors will shift lean, dropping to about 0.1V. So the easy way to assess how the upstream sensors swing is to bring up a live data graph on your scan tool, sit in the car and stomp on the throttle. At fast rpm you should also see more rapid swinging of upstream sensors between rich and lean, and a lazy sensor may not keep up with the other sensor on the opposite bank. That's also a useful trick to investigate lean trouble codes. A vacuum leak will instantly improve when you snap the throttle, whereas a bad MAF or bad fuel delivery will worsen at snap throttle.
Any less expensive scan tool you'd recommend? Something in$500 range 🤔
I haven't yet found a scan tool that I didn't learn to hate. Some guys say nice things about the Launch. I would not recommend Autoenginuity, it has too many bugs. Autel is pretty good but subscription fees are outrageous if you want to stay up to date. I've always wanted to try a used SnapOn scan tool, you might find one on ebay for cheap. There are some really cheap tools that can run off a phone that might be worth a try. All big scan tool companies have many versions, with a huge price range, but for starting out all you need is a code reader and something that offers live data.
i tested 3 sensors and all have about 3 ohm resistance, but all heat up too slow , i tested wires , i installed 12v bulb and it blinks when i turn key for contact and when engine is started, any idea?
With engine on at cold startup you should get either a continuous glow of that bulb or repetitive high frequency flashing. Some computers will turn off the heater circuit if the circuit is shorted to ground or has a trouble code, so you might try writing down and then erasing the code, then try again. Aftermarket sensors may not behave the way the computer expects so that may be an issue.
Thanks ,very educational
I have barometric pressure too low (P0129) and all four 02 sensor heater circuit high codes. Anyone have any idea what could be wrong? Also barometric pressure light turns on without starting vehicle
I'll throw out a guess those two are unrelated. Don't forget the easy fix, the fuse for the heater circuit which would take out all four at once. Hopefully the PCM driver itself is OK. Once fixed, you may need to erase codes for the PCM to give it another try. It's not uncommon for barometric pressure gauges to go bad. I'd seek out the sensor in question, check power and ground to the device. Check alldata to find your vehicle and see manufacturer details that will guide further testing. This might be one of those devices that sends a variable voltage to the PCM. If so, to evaluate the sensor wire you can apply a tiny voltage complete with current limiting resistance by using the diode function on your multimeter, then look at a scan tool for change in value to verify circuit and PCM continuity. Never test the PCM with external voltage and no resistance because you could fry the PCM. if all is well, change the sensor.
If your getting po135 thats a bad heater right? If the heater turns itself off anyway how will that code affect the running of the car or does it?
Good question, I'm surprised nobody asked that before. There is very little effect on the car except the pesky check engine light on the dash, especially for oxygen sensors that are downstream of the cat. Environmental protection laws are built into the algorithms, which is why they demand a trouble light. Without the heater, the car will go into closed loop a couple of minutes slower, increasing emissions at first start. I'm told Chrysler does use the downstream sensor 2 data to adjust fuel trim, but most other manufacturers use the downstream sensors purely to assess how well the catalytic converter is working. The upstream sensors are more critical, and I wouldn't hesitate to change those because you'll get brisk return on your dollar by improving fuel economy. Newer broad band oxygen sensors require a much hotter sensor to work properly, so the heater is more critical for those.
@@spelunkerd My Tahoe's getting a po135 bank 1 sensor 1 code heater malfunction so if i just leave it be and clear the light whenever it comes on it wont affect engine performance? Im just trying get an idea on how these work but id probably be better off just replacing it
@@roltyd22 Sensor 1 is upstream of the cat, so it is used for engine performance, but it likely starts working within a few minutes from the generated heat of the cat anyway. So, it's not urgent, you could leave it. But that light will be annoying, and if other problems arise you may not know it because the light is already on. And if you want to sell the vehicle, resale value is dramatically less if the light is on. As I showed, replacing the sensor is pretty easy, and if you don't have the right tools a mechanic could do it easily. So for all those reasons it is probably best to bite the bullet and replace it. Also old sensors get 'lazy', which does affect fuel economy.
good video but my problem I got check engine with p0130 p0135 p0141 p0155 p0161 p0136 codes all at once I don't even know where the problem might come from.
Please tell me the resistor value. THANKS
Scroll to 7:52, it's written in the video for this vehicle and this sensor, (3.5-14 ohms). My new sensor was out of spec at 15.1 ohms. Every vehicle is a little different so if you have a different make and model, expect some variance. For dealers specs I use alldatadiy, although their long term subscription fees have escalated quickly.
wow❤
so for a 04 Chevy Avalanche Bank 2 is the passenger side?
Yes.
@@spelunkerd thank you
⚡RAIN MAN⚡
You should have run a tap in that hole. You should be able to screw those in with your fingers. Unless GM has changed the type of the O2 sensors they used when I worked on them, I would say the new looks like it is not a OEM part. I retired from working at a GM dealer in 2002, so I could be wrong. But the one you removed looks OEM for sure. Unless you got that from a GM dealer, I would question it being real. There are a lot of parts online claiming to be OEM, but they are not. Most aftermarket electrical parts almost never worked properly.
Those are good points! I did get the part at the local dealer, but even so GM have outsourced their parts so you never know. It's working fine, and for a downstream sensor it should be fine. I do have a thread chaser set so the only thing holding me off using it was laziness. In the end it spun on fine. Thanks for stopping by!
AC Delco is using Denso as their primary supplier so some things have changed in the past few years.
how bypass 02 senior on dodge ram 1500..i have straight pipes and not cat.
In older vehicles the data from sensors placed downstream of the cat are there almost entirely to assess the function of the cat. So, even if unplugged there should be little effect on fuel mileage or fuel balance. The PCM will trigger an unavoidable check engine light and trouble code. The vehicle will fail emissions testing if you live in an area demanding it pass, but the vehicle should drive fine.
@@spelunkerd I will put fouler on
@@bubbaclaypoole7579 With no cat at all I'd be surprised if any extender would be long enough to flatten the rich/lean curve. It seems like a lot of work when you could simply apply black tape over the light on the dash.
@@spelunkerd I can jump the senders with resit..i cant spell word im a old shade tree mechanic..lmao
@@bubbaclaypoole7579 A simple resistor works for air bag circuits and even some first gen security circuits, and there is some internal resistance to the signal part of an O2 sensor. But recall that O2 sensors actually produce voltage and tiny current after they warm up, much like a battery within a narrow range which the PCM is looking for. When the cat is working properly the normal wide swings of voltage are flattened out within a specific range. Some circuits also have a bias voltage used by the PCM to look for opens and shorts. It would be tricky to try and mimic a normal O2 sensor closely enough that the PCM is not able to detect a problem. You also have two sides to the circuit, with a heater side that needs to be approximately right as well. For the amount of fiddling it would take to try and get it right, I'd just live with the dash light.
Dodge ram v8 will trip asd pcm?
That's never happened in my old '98 Dodge but in about 2002 Chrysler moved to an ASD relay inside the TIPM, which was problematic because of corrosion. Through the next decade TIPM corrosion and various issues became notorious.
Its a 2001 ram auto/rwd the tipm has only relays in and on it no curcuit board
I think whoever designed that system was deranged.
I just replaced my sensor coz that's WHT the scanner is telling me..
Now the check engine lights up again now its the heater sensor
If it's the identical sensor again, then possibly the aftermarket sensor is not recognized as correct for your car. Aftermarket sensors are a lot cheaper but don't always play nice with the OEM equipment. Alternatively if it is the identical trouble code then possibly you've got a problem with wiring or the connector. Work it up as shown in the video and you'll likely sort it out.
@@spelunkerd thanks for the answer i bought that sensor for 12k pesos here in the philippines and they said its an original i hope it just the wiring like the seller said when i return to him
@@joenelsaracho4836 If the heater has burnt out, it would be easy to prove that with a multimeter set to ohms. You never know when you buy used parts.
66 like my dear friend
Please don't teach people to poke the probe thru the wire insulation. This is where corrosion is going to start in about 2 months.
Although I understand your point, remember that this is the part I'm throwing away. The new sensor comes with that length of wire up to the connector. Were I not to throw away that wire, it is easy enough to fix with liquid tape. Professionals puncture wires every day, and if repaired correctly there is no issue even if they continue to use that wire. There are of course alternate approaches. I have a $400 set of breakout T connections that require front probing with correct size taps. When the wrong size is chosen, corrosion or loosened connections can start there. And of course there's the old inexpensive standby of backprobing with a fine needle, again vulnerable to eventual water ingress when you slide that needle along the rubber seal. So, various options, all carry some risk. Remember that if you're trying to measure response with a scan tool, or if you're doing simple drop testing, you need the connector be fully hooked up to assess response. Even front probing one side of the connector carries risk. I remember ScannerDanner rolling his eyes at remarks like this. What method would you use? Or, do you play the parts swapping game and forget accurate diagnosis?