O2 sensor heater codes

WILKOM

MEMBER
2005 DODGE DAKOTA
4.7L
V8
4WD
AUTOMATIC
113,700 MILES

Check engine light on. All 4 heater O2 sensor heaters reading low. Replaced two and no change. Only common point they have is ground and it checked out good, Is there any other sensor or signal that could be stopping them from heating?

Looking for any ideas to check.

Thanks

9 Replies

94 TRANSAM

MECHANIC
680 POSTS

You need to clean your mass airflow sensor.

https://www.2carpros.com/articles/mass-air-flow-service

Let me know if this takes care of it.

Rich

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Wednesday, March 11th, 2020 AT 11:39 AM

KEN L

MASTER CERTIFIED MECHANIC
48,363 POSTS

I have seen this problem before and replacing the PCM fixed it. The heater driver goes out which is internal to the PCM. Here is the location to the PCM and instruction on how to replace it in the diagrams below. Check out the diagrams (below). Please let us know what happens.

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Wednesday, March 11th, 2020 AT 2:43 PM

WILKOM

MEMBER
25 POSTS

Rich and Ken, thanks for the responses. Since it is easier faster and cheaper, I'll do the MAF first hoping that will do the trick. I had been investigating and considering the PCM as well, but hope to leave that as the last resort. I am thinking that I can check the PCM by using a volt meter to check for power to the sensors before committing to replace it.

If the MAF cleanup doesn't work, I'll be back to discuss the testing of PCM.

Thanks for the suggestions it gives me some items to eliminate to resolve the problem. Will let you know progress.

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Thursday, March 12th, 2020 AT 4:49 PM

94 TRANSAM

MECHANIC
680 POSTS

I just had this exact same issue with my car a few months ago and my MAF was filthy. If the cleaning doesn't work I would try replacing the MAF before jumping to the PCM. Much cheaper and less hassle.

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Thursday, March 12th, 2020 AT 8:35 PM

KEN L

MASTER CERTIFIED MECHANIC
48,363 POSTS

I am not sure if the MAF sensor will affect the oxygen sensor heaters but you never know. Please let us know whats happens.

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Saturday, March 14th, 2020 AT 11:56 AM

WILKOM

MEMBER
25 POSTS

Thanks for all the advice. Finally got frustrated not being able to find a problem to fix, broke down and got an ECM from carcomputerexchaange. Com.

Installed it a few days ago and the problem was resolved. Because the unit has a jelly like heat sink, I didn't try to see if I could see damage in the bad one.

Now my only headache is getting the drive cycle to complete to pass inspection.

Thanks again and stay safe in there.

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Saturday, March 28th, 2020 AT 6:59 AM

KASEKENNY

MECHANIC
18,907 POSTS

Here are the driving procedures to force the monitors to learn. Basically this will take an hour or two of driving but it will force them to run. However, it is helpful if you have a scan tool that you can check the status of each monitor after the specific drive procedure. Hopefully this will help get them to run rather then waiting for them to run under normal driving.

Just make sure you clear codes before starting all these.

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