System Too Rich P0172, P0175 from a blown O2 heater fuse (Jeep)
ฝัง
- เผยแพร่เมื่อ 4 พ.ย. 2011
- This video applies to Chrysler, Dodge and Jeep systems. O2 sensor and O2 heater circuit problems may cause the computer to lean out the air-fuel ratio excessively causing the vehicle to have low power and not accelerate. However it will run good cold and at wide open throttle.
Engine Performance Diagnostics Chapter 5 pages 11-22
Symptoms
- low power
- runs good cold and at wide open throttle
- hesitation on acceleration
- rough idle
- check engine light with O2 sensor heater codes
Fix
- replace blown fuse for the O2 heater
Tests shown
- how to test an O2 sensor heater circuit
- how to understand fuel trim
- how to use scan data O2 bias voltage to determine O2 heater operation
- how to test an O2 sensor signal with a scan tool
Related videos
- What can cause an O2 sensor to read near 5 volts? (Chrysler bias voltage) • What can cause an O2 s...
- WARNING! Aftermarket Oxygen Sensors (Chrysler part 1)
• WARNING! Aftermarket O...
- WARNING! Aftermarket Oxygen Sensors (Chrysler part 2)
• WARNING! Aftermarket O...
Playlist
- (Chapters 4 and 5) Fuel Trim and Oxygen Sensor Testing
• (Chapters 4 and 5) Fue...
For more information on this topic, I have written a “field manual” called Engine Performance Diagnostics which is available at www.scannerdanner.com as an eBook or paper book.
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Disclaimer:
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no problem man and no need to apologize. thank you again for your support and i am glad you found the answer you were looking for in my eBook
Such great info! Treasure in these Scanner Danner vids. Watch em all! Then watch them again and again. One reason I have premium is to thank Paul for all this great work!!
Thanks Bill!
Amazing to see the progression in your video presentation compared to this earlier video. The great thing is that this information is as valuable now as it was 7 years ago 👍
Thank you for making this video. My wife's car is having a very similar problem I can't look at O2 sensor data but I can check to see if they're warming up... and all the short-term and long-term fuel trims are maxed out.
maxed out positive or maxed out negative? What codes?
I don't usually comment(Maybe 2 or 3 comments for the 5 years I've been on TH-cam), but what an excellent video and explaination. Thank you!
Well thanks so much for taking the time to comment. Much appreciated. I read every one of them.
Great video partner, very professional and laid out in a no BS manner, loved it👍👍
Glad you enjoyed it, thank you!
I learned about you at an O'Reilly Tech Class. Great info. I'm a VW Audi Porsche Tech.
how cool is that! Thank you
DAMN I love em thick
monica93304 you go women😛😋
5:29 Good ground for sure👣
Thank you paul you gave a very useful info thank you very much 👍👍👍👍👍👍
no this is the signal wire bias voltage we are looking at.
check out my Jeep Liberty case study on this same subject for more info.
the heater circuit is grounded on the block and powered from the ASD relay
@fivefortyeye540i You could call it that. In this case it is used for heater circuit diagnostics. On other sensors you can have a ground bias used to reduce noise in the circuit.
I am a better tech because of you thank you for sharing your knowledge
Great video! Well done!!
Great video thank you for professional advice 👍🏿
@pimp48934 How far does the spark jump out of the coil? It should be a bright blue arc that jumps out at least a half inch to an inch of an air gap. If the coil is weak, this could produce your symptom. Something else to consider is a jumped timing chain or shifted flywheel. This would alter when the spark is occurring in relation to TDC and therefor rotor to cap air gap as well. Are there any trouble codes?
@frosty9595 It may or may not, I know Chrysler used a separate O2 heater fuse on some and on others heater power was supplied on the ASD circuit. My Jeep no start case study, was ultimately caused by a shorted O2 heater wire. No separate fuse for that on. I just depends on the year and the model
Great vid 👍
Question tho, does this test only applies to only Chrysler, Dodge, and jeep? I’m a honda guy... thanks!
great job on explaining this
thank you! It is a difficult subject for sure.
Here is another video I did to reinforce this topic
th-cam.com/video/v8XrM-7BuOg/w-d-xo.html
could be, do some O2 response testing (add propane see if it goes full rich)
Great video!
very good ! help so much
Thanks you solved my problem
@pimp48934 I do not like that it will not run with the old PCM. If the used PCM is of the same model and engine I don't think that will cause it to run rich. Reprogramming can only be done with a factory scan tool and access to factory information. Is it possible you mixed up your firing order in the process of changing all these parts?
My Dc is 100% on rear 02heater, constant. Sensor stays steady around 700mv. Wondering if I have a wiring problem since the cat is heating it with it at 100%. On my neon.
@MrLoboreview Sorry I don't, I do training at our school (Rosedale Technical Institute) for snap-on for the Solus, Verus and Vantage Pro.
Hi Paul. Great video. I watch them all even when my car is running fine. Struggling to get my head around a problem with my vauxhall zafira b petrol 1.6 at the minute. I have a lean code come up yet the smog test reveals its running rich. Fuel trims go - when parked with increased rpm upto 3700 but when I'm driving then they go +27%. It's a map system with iat senor. I'm thinking pre cat 02 sensor although going lean and rich, is telling pcm it's running lean and sets a lean code but computer is adding fuel making exhaust rich. 02 sensor goes as low as 0.05 to 0. 9. Could it be stuck more on lean side causing pcm to set lean code yet adds more fuel making exhaust rich? Fuel trims go +27% while driving. Would really appreciate your expertise as I'm an enthusiastic (amateur) auto electrician who loves this stuff. I've had 4 auto electricians look at it but can't work out what's wrong. Really appreciate your help. Michael c .
I have a 2008 Lexus gs350 both banks running rich and I have a p0055 code which is an 02 heater resistance bank 1 sensor 3. Could all that be related? Good hunt down man!
This is exactly why I check all four wires on an oxygen sensor(just out of habit) Even with a low or high signal DTCs. I have seen a fixed rich(false rich report)even with a good heater circuit so just keep these variables in your head.
Paul are you looking at voltage on the heater circuit control (ground side) when it's cold it's 5v and as the heater warms up the voltage drops to near zero volts? Something I've never really llooked at before .
Hey, Paul. I am trying to know if a stuck open thermostat can cause an oxygen sensor code or heater circuit code. From my understanding, a stuck open thermostat will keep the vehicle in open loop, and in open loop, the o2 sensor is not used.If it not used, the pcm is not going to monitor it. Could you please help?
Paul,do you remember where you got your Vantage test leads? I can't seem to find threaded tip test leads to fit my bed of nails alligator clip.
@ScannerDanner ok thanks alot ill give that a try tomorrow and let u know what its doing
@Username64870 Are you talking about ohm testing the O2 itself or the wiring? If you are talking about the O2, there would never be a need to ohm the sensor side of the O2. First there are no specs because temperature of the O2 changes the resistance of the sensor. If the senor is cold it is basically an open circuit. If the sensor is hot its resistance drops drastically. However if you did ohm test it you would not hurt it.
I have an 02 dodge caravan and I don't a a heater fuse. could it be called something else?
I bought those from the snap on tool truck.
computer electronics theory would be the same. inputs, outputs, transistors, solenoids would all be identical types of tests. I just do not work on them as we have very few diesel powered cars in the US
Excelente
Reminds me of the 1996 jeep no start videos
only after a period of time with a fixed O2 signal. this is why you will have intermittent conditions with this
hey bro do you have a video on how to use the verus, modis or so.....?
I own a Audi and I have a bank 1 rich and bank 2 as well as lean for bank 1 and bank 2 with a code that says bank 2 sensor 1 02 is not detected could this just be a 02 sensor throwing a rich and lean code? I'm confused please help
I bought those from the snap on tool truck
Paul I have never seen you working on diesel engines
and i' m asking if there are differences in the methods
and theories.
my 04 scion xa -45 fuel trim! ( at it's worst) I hope it's the fuse! checking asap btw im getting 3 codes, p0133, p2196, p0172 just checked the fuses. there good. don't know what to do
throttle body is spotless as well. this tracker is really chappin my ass
I got a 2001 g cherokee 4.0 with an oxygen sensor code b2s1, replaced sensor and now getting a p0174 bank 2 lean. Computer is adding 30% fuel to bank 2. What do u think? Maybe a defective sensor?
Hey ScannerDanner! I have an 04 Hemi Ram with a shared heater return circuit for bank 1 and bank 2 (says the manual), code is P0052 (B2S1 Heater control circuit high) currently ONLY bank 2 has an issue with fixed voltage at 1.72 volts. Can a bad bank 1 sensor that looks good cause bank 2 to go crazy in this scenario with a shared heater return?
I'm fixed at 1.72 volts on bank 2 and it does NOT move, all of my symptoms are identical to this video. I bought a new replacement bank 2 02 sensor, direct wired all 4 wires to the pcm to eliminate possibility of a short or open, put my backup pcm in to rule out that and currently I have zero luck and the same symptoms are still there.
Great video Paul! Does the heater circuit work full time or does it shut down ? Worked on A 04 wrangler with a 4.0 and heater circuit turned off when vehicle warmed up. Only monitored this once and that's what happened. Will need to look at a wiring diagram tomorrow for sure. Whats your thought? Vehicle sets po135 heater circuit malfunction. Thanks Paul.
On some systems they work full time, on others they are turned off at times and on still others they are pulse width modulated.
+ScannerDanner my 2000 jeep cherokee will warm up then backfire through the throttle body when given more than a 1/4 throttle then it stalls out
@ScannerDanner i thought the same thing but the firing order is right ive checked it three times and idk why the old pcm wont work something has to be messed up in the old pcm but like i said the new one runs just acts like a plug isnt firing
i changed the coil today and it fired up but now its running real rich and i think its cause the new pcm i bought used and didnt flash it to my vehicle and i also tryed putting the old pcm in and it wont run at all with the old one so now im stuck again it acts like a plug is fouled but i also bought new plugs and put them in helped a little but still runs like shit.. And also if i do have to flash the new pcm i have how do i do it can i get a scan tool and do it or what??? thanks for thereply
Excellent.
I've watched a few o2 vids and I don't think I've heard; what is the DOWNstream o2 supposed to read on a good working system at around 2000rpm. Upstream goes above and below 450mv fairly rapidly but what should the downstream read? Thank you.
If that cat is good the downstream sensor should NOT be fluctuating like the upstream. It should be steady.
Cool
Batman's obd scanner. "The Batscanner".
newby question: that Downstream O2 was reading 0.04V.... but i thought normal operation is 450mV +/- 300mV... so how is 0.04V normal here?
I'm curious. If the sensor is not functioning, shouldn't the computer stay in open loop?
Hi friends I heard that Ohm testing O2 sensor signal wire with DMM meter (not heater)might damage O2 sensor! Is that true?
My toyota vios 2003 AT has long term furl trim of -8 to -13. What does it mean? And what should i do to make it near 0?
Thank you 🙏
That is an indication of a rich condition and there are many causes for that.
i have a 97 jeep grand cherokee that has no spark out of the distributor but have it at the coil and i changed everything the cap rotor wires cam and crank shaft sensor and nothing and the rotor turns also so i have no clue why i have no spark out of the distrbutor please help danner
and also i believe the pcm that i got was off a jeep that had the tow package and mine doesnt idk if that would cause it to be running like that and i really dont wanna spend 200 more dollars on a new pcm
crossing my fingers and holding my breath as I go run these test
If you need additional help, post to my forum. It is free to join and we can definitely help you!
www.scannerdanner.com/forum.html
@@ScannerDanner thanks' I may do that this trucks kicking my ass.
5:29 That battery terminal👀
Bias voltage?? Is that a reference point ?
cool
This kind of problem shouldn't happen on a vehicle without bias voltage right?
That is correct my brother
@pimp48934 And also its just getting to much gas the computer has to be telling the fuel injectors to shoot to much fuel its carboning up all the plugs. It has to be tht computer i got the one my jeep had in it was a aftermarket one then the new one i put in was the factory one from another vehicle
hey I have a 97 grand Cherokee with common problems I had changed the O2 sensors before and switched the cat but the truck kept running rich and ruined all of them where's a good place to start looking for the problem I have already checked my fuses and they're all good. thanks in advance
Watch my video about aftermarket O2 sensors on Chrysler / Dodge vehicles
Same?
I have toyota prado 2010 its having p0175 p0172 p1605 what should i do any help....
www.scannerdanner.com/forum/post-your-repair-questions-here.html
This is a link to my forum. It is free to join. Hope to see you there.
i got a 02 tracker 2.5l, it runs good but sometimes while idle it starts to drop rpm and stall, hit the gas and its fine. i got p0175,172,447,141,161. it ran for ever with the last 3 but now it stubbles at idle sometimes and stalls. any ideas?
check fuel pressure, do an injector balance test, look for a leaking fuel psi reg. (if it is a return type system). stuck open canister purge valve, sticking open EGR, head gasket leak (contaminating the O2s and causing a false rich). I have videos on all of these. Thanks!
fuel pressure while running is 38 psi which is normal for the car. when i pinch the return line it goes up to 70-80 psi. i cleaned the egr (it opens and closes fine), cleaned idle aire control valve, checked to see if the reg is leaking (its not). doesnt show signs of a head gasket leak (coolant level has always been perfect).
Injector balance test would be my next test. Or possibly a skewed MAF sensor. (cleaning will NOT fix this)
Is there another name for this fuse by chance?
Is this just a Chrysler design?
@pimp48934 Yeah i went out and tryed pulling the plug wires and it didnt really run any different and they all spark so i have no clue whats going on it just runs like shit and i had it wot and it just back fires like a bitch and it blew my exhaust apart so i dont know im ready to scap this damn thing but its my only vehicle
downstream shouldn't be arround 0,5V ? maybe when driving.
I'm having the exact same issue on my 03 ram 1500 5.7 hemi. Cant find any info on the O2 system though. I don't know which wire is the heater wire. It's not a fuse though. And I've put 3 sets of O2 up and downstream. The 2nd set would not communicate. (Faulty). Ltft -33% stft 0-(-33%). 1/2 PWM O2 Heater 100% and will not change
The heater circuit is the two white wires (sensor side). Watch my video where I'm warning about aftermarket O2 sensors of Chrysler system
Thanks for the reply. I learned that the no brand name ones were junk. The set that's in there is NTK I believe. I paid the extra dollar for them. I'm going to check the wires tomorrow. I'm hoping that it's just the O2s. I have a brand new computer I installed because the heater issue after the 3rd set of O2s. Didnt change the readings unfortunately. Thank you for the video and reply!
Okay good, you have NTK sensors in there, that is what you want. I just checked a diagram and the O2 heater circuits are pulse width modulated on the power side of the heater. The ground side of the heaters go directly to ground (G107 - right rear of engine compartment). So what this means is the PCM will be pulsing voltage on that circuit and if you use a regular digital multimeter, you will only see an average of the pulse. An incandescent test light would be your friend on this circuit as you will be able to see the bulb flashing on/off.
Hey ScannerDanner, thank you for the information. I just finished checking the G107 (above the PCM) with a light. No luck, all the grounds are solid light. Also, my BR/WT wire from the PCM is showing 0.3 DCV. I've been working on this truck for about a year now. Ever since I broke a valve spring cyl. 3 exhaust and bent the push rod. I rebuild the heads and replaced nearly every sensor on the truck (minus Cam and Crank). I took it to a dealership which was the worst mistake. They said my cat and O2 sensors were the issue. I asked how they tested the cat. They said the vacuum. I did an exhaust back pressure test when I took it home and it was less than 1 PSI. I replaced the O2's multiple times and no luck. Its gotta be something silly that I'm missing. I almost wish I had an oscilloscope right about now...
I did some more tests. PCM output is 3.3V, Heater wire at the O2 is 13.5V, O2 Signal wire 2.5V. Doesn't make very much sense. Why there's 0.8V difference other than resistance possibly in the wire. Would you happen to know what resistance I should look for with O2 cold? Possibly another bad O2 sensor?
could this apply to my 2008 impala?
Not likely
@@ScannerDanner i don't think so either. mine has the p0420. i think because of the cat replaced with an aftermarket. but my car has not had a code thrown on it for well over a year.. the garage said it had the 172 175 i never seen it on my scan tool or auto zone.
DODGE DAKOTA HEATER CIRCUIT P00038 POOO52
Good video but you don't have to yell, we can hear you loud and clear lol 🤣😂
early video, sorry. What you are not seeing is I am teaching to a group of students at our school and I am projecting my voice for them to hear me, not realizing the camera mic is right next to me :-(
I've gotten a lot better since 2011
ScannerDanner just giving you a hard time. Good information to learn
and rightly so! I hate watching my old videos. Great content, just poor filming and audio on some
What about a 1999 Jeep Wrangler? There is no fuse in this location.
I believe in 99 they changed it to a PWM heater circuit for the O2.
Did you just replace it and are now having issues similar to what you see here?
@@ScannerDanner I had changed the o2’s with Ntk’s and changed MAP sensor. Only code I keep getting is the p0172. Today I did eliminate the heater as the voltage was about 5 till I started Jeep and then went down under a volt. Only slight leak I have is exhaust manifold that had been there with no fault. I even tried just for test purposes only to space the upstream sensor. By the way like to watch your videos and to bad you were not here in lower central NY. Thanks for reply as well.
@@carlmccartney1323 okay perfect, what are your STFT and LTFT fuel trim numbers at idle and 2500 rpm in park
@@ScannerDanner Long term are at -32 and short term are positive to start and then as warms go negative as well. I did not try at 2500 rpm’s.
Also I did not mention, I was thinking possible fuel injector leak. But I get no misfire and I pulled all the plugs to see if there was any gas or extra fouling. But they were all the same.
I bought those from the snap on tool truck