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.