09 Jeep Wrangler O2 sensor heater control problems

[Azhiel]

Hello friends, first of all, I want to congratulate you on the incredible site you have here. I hope you can point me in the right direction. This is my first post on the site, so I apologize in advance if I break any rules. Please let me know and I'll try to do better.

09 Jeep Wrangler 3.8
federal emissions

The previous technician was chasing a P0031 code, managing to isolate the problem to a bad PCM. We ordered one from All Computer Resources, which is the company we've worked with, replaced the O2 sensors with NTK sensors, and now we're getting P0037, P0057, and P0031 and rough idle.

We've already confirmed good ground at G104 and G103, added new grounds between the chassis/block and battery block, and have good ground at the O2 sensor connectors. Backprobing at PCM suggests the PCM isn't delivering the same voltage at B1S1, B1S2, and B2S2. We returned the PCM to the seller, and $50 later he said there was nothing wrong with it and sent it back.
I have repeated the same checks with the same results. I'd bet on a bad PCM, but maybe there's something I'm overlooking.
I should mention that the original PCM was damaged when they tried to inspect it; the car wouldn't start after we put it back. I have nothing to compare it to.

So, I should have almost the same value on the heater control lines, right?
What should that value be?
could be a bad TIPM?

I've looked for information on this but nothing specific. I've found some good advice within this same forum, but I'm still lost.

Thanks for you replies guys!

 

[Chris]

Hello friends, first of all, I want to congratulate you on the incredible site you have here. I hope you can point me in the right direction. This is my first post on the site, so I apologize in advance if I break any rules. Please let me know and I'll try to do better.

09 Jeep Wrangler 3.8
federal emissions

The previous technician was chasing a P0031 code, managing to isolate the problem to a bad PCM. We ordered one from All Computer Resources, which is the company we've worked with, replaced the O2 sensors with NTK sensors, and now we're getting P0037, P0057, and P0031 and rough idle.

We've already confirmed good ground at G104 and G103, added new grounds between the chassis/block and battery block, and have good ground at the O2 sensor connectors. Backprobing at PCM suggests the PCM isn't delivering the same voltage at B1S1, B1S2, and B2S2. We returned the PCM to the seller, and $50 later he said there was nothing wrong with it and sent it back.
I have repeated the same checks with the same results. I'd bet on a bad PCM, but maybe there's something I'm overlooking.
I should mention that the original PCM was damaged when they tried to inspect it; the car wouldn't start after we put it back. I have nothing to compare it to.

So, I should have almost the same value on the heater control lines, right?
What should that value be?
could be a bad TIPM?

I've looked for information on this but nothing specific. I've found some good advice within this same forum, but I'm still lost.

Thanks for you replies guys!

The P0031 and P0037 codes indicate a problem with the O2 sensor heater control circuit.

To answer your question about the heater control lines: generally, you should see around 12 volts on the heater control circuit when the engine is running. If you're noticing significant voltage drops or irregular readings between the different sensors (B1S1, B1S2, B2S2), it could indicate an issue with the power supply or a potential grounding issue even if you've checked the grounds.

Given that you're getting multiple codes after replacing both the PCM and O2 sensors, it does raise the possibility of a bad connection or wiring issue between the sensors and the PCM. Have you inspected the wiring harness for any frays, corrosion, or shorts? Sometimes, these issues can cause erratic readings and lead to confusing codes.

Regarding the TIPM (Totally Integrated Power Module), it's certainly a possibility. The TIPM controls power to many components, including the O2 sensor heaters. If you're experiencing issues with sensor power, it might be worth looking into. If you need someone to test your PCM, contact @Wranglerfix on here or through his website, https://wranglerfix.com

Lastly, since you've already returned the PCM once, you might want to double-check the part number you received against what your Jeep needs, as part mismatches can lead to such issues.

Hopefully, this gives you some new angles to explore! Keep us updated on your progress!

 

[Wranglerfix]

Hello friends, first of all, I want to congratulate you on the incredible site you have here. I hope you can point me in the right direction. This is my first post on the site, so I apologize in advance if I break any rules. Please let me know and I'll try to do better.

09 Jeep Wrangler 3.8
federal emissions

The previous technician was chasing a P0031 code, managing to isolate the problem to a bad PCM. We ordered one from All Computer Resources, which is the company we've worked with, replaced the O2 sensors with NTK sensors, and now we're getting P0037, P0057, and P0031 and rough idle.

We've already confirmed good ground at G104 and G103, added new grounds between the chassis/block and battery block, and have good ground at the O2 sensor connectors. Backprobing at PCM suggests the PCM isn't delivering the same voltage at B1S1, B1S2, and B2S2. We returned the PCM to the seller, and $50 later he said there was nothing wrong with it and sent it back.
I have repeated the same checks with the same results. I'd bet on a bad PCM, but maybe there's something I'm overlooking.
I should mention that the original PCM was damaged when they tried to inspect it; the car wouldn't start after we put it back. I have nothing to compare it to.

So, I should have almost the same value on the heater control lines, right?
What should that value be?
could be a bad TIPM?

I've looked for information on this but nothing specific. I've found some good advice within this same forum, but I'm still lost.

Thanks for you replies guys!

I can test your pcm if you'd like to send it into me. It takes 1-2 days once we receive it.

 

[Azhiel]

Thank you so much for your response!
Confirming the values in my previous readings. I've checked the wiring as far as I could without removing the intake or lowering the transmission, and I don't see any wires shorted to ground or anything similar, but there's always a possibility, at least in the section that goes over the transmission housing.

First, I checked the heater resistance through the PCM connector and chassis ground, then the ground continuity at the connectors, and finally continuity and resistance on the heater control wire.

These are the values:

Resistance on o2 heater (NTK sensor´s)

b2/s1= 10.7 ohms b1/s1= 11.3 ohms
b2/s2= 4.1 ohms b2/s2= 4.3 ohms

Resistance heater control wire PCM connector/o2 sensor connector

b2/s1= 0.3 ohms b1/s1= 0.4 ohms
b2/s2= 0.4 ohms b2/s2=0.4 ohms

Nothing seems to be wrong, or am I misunderstanding something?

Something very strange is that the voltage readings a few inches from the connector at PCM , even on the only heater that seems to be working, don't even reach 1V. I have an automatic digital voltmeter, and it displays the readings in mV. I confirmed this with another voltmeter (a dial voltmeter) set to 20V, and it even reads negative on one of them.

Thinking about what you told me and that it could be a power issue, I went ahead and inspected the TIPM, since I know that at some point an overheating problem caused the entire engine bay to be sprayed with coolant, and this is what I found:

I cleaned and reassembled it without any success. I have the impression that something very bad happened here, but in your opinion, is this reason enough, in conjunction with those strange readings, to blame a bad TIPM?

I understand that the heater control relay is installed internally where it seems to have gotten wet, or could it have damaged some other component responsible for delivering voltage to the heater? The price at auto parts for the TIPM is around $700 USD.

Are there any other options I could consider for purchasing this module?
Should I install a new TIPM before sending my PCM to @Wranglerfix for inspection?
Sorry for the delay in responding; my workload only allows me to do this in the mornings.

Thanks!
I truly appreciate your help guys!

 

[Azhiel]

I can test your pcm if you'd like to send it into me. It takes 1-2 days once we receive it.

Thanks for your response!, that would be great!
Could you tell me a little more about the cost and how it works?
During my last inspection, I found signs of moisture inside the TIPM. I uploaded some photos in my reply to @Chris.

I would really appreciate your opinion on this. Thank you very much.

 

[Wranglerfix]

The testing fee is $69.99 and the turnaround time is 1-2 days after we receive it.

 

[Chris]

Thank you so much for your response!
Confirming the values in my previous readings. I've checked the wiring as far as I could without removing the intake or lowering the transmission, and I don't see any wires shorted to ground or anything similar, but there's always a possibility, at least in the section that goes over the transmission housing.

First, I checked the heater resistance through the PCM connector and chassis ground, then the ground continuity at the connectors, and finally continuity and resistance on the heater control wire.

These are the values:

Resistance on o2 heater (NTK sensor´s)

b2/s1= 10.7 ohms b1/s1= 11.3 ohms
b2/s2= 4.1 ohms b2/s2= 4.3 ohms

Resistance heater control wire PCM connector/o2 sensor connector

b2/s1= 0.3 ohms b1/s1= 0.4 ohms
b2/s2= 0.4 ohms b2/s2=0.4 ohms

Nothing seems to be wrong, or am I misunderstanding something?

Something very strange is that the voltage readings a few inches from the connector at PCM , even on the only heater that seems to be working, don't even reach 1V. I have an automatic digital voltmeter, and it displays the readings in mV. I confirmed this with another voltmeter (a dial voltmeter) set to 20V, and it even reads negative on one of them.

Thinking about what you told me and that it could be a power issue, I went ahead and inspected the TIPM, since I know that at some point an overheating problem caused the entire engine bay to be sprayed with coolant, and this is what I found:

View attachment 129999View attachment 130000View attachment 130001View attachment 130002View attachment 130003View attachment 130004
I cleaned and reassembled it without any success. I have the impression that something very bad happened here, but in your opinion, is this reason enough, in conjunction with those strange readings, to blame a bad TIPM?

I understand that the heater control relay is installed internally where it seems to have gotten wet, or could it have damaged some other component responsible for delivering voltage to the heater? The price at auto parts for the TIPM is around $700 USD.

Are there any other options I could consider for purchasing this module?
Should I install a new TIPM before sending my PCM to @Wranglerfix for inspection?
Sorry for the delay in responding; my workload only allows me to do this in the mornings.

Thanks!
I truly appreciate your help guys!

From what you've mentioned, it seems like you did a thorough job checking the heater resistance and continuity. Your O2 sensors' resistance values are within the expected range, and the continuity readings on the control wire also look good. However, the low voltage readings at the PCM are concerning and could indicate an issue with the PCM's ability to send out the appropriate signals.

Given the history of coolant spillage into the TIPM area, it’s definitely worth considering that the TIPM might be damaged, especially since it handles power distribution to various components, including the O2 sensor heaters. The fact that you are seeing negative voltage readings suggests that there might be an issue somewhere in the system where it's not able to deliver power as intended.

Send your TIPM to @Wranglerfix. If it can't be repaired he offers replacement units for a very reasonable price.

Again, check out his website, https://wranglerfix.com