Code P0A9C, Hybrid Battery Temperature Sensor?

BEACHCOWBOY

MEMBER
2019 JEEP WRANGLER
2.0L
4 CYL
TURBO
4WD
AUTOMATIC
120,000 MILES

Experiencing a check engine light due to the hybrid battery temperature sensor range/performance. This is the 48V battery as part of the E-torque system. Keeping the vehicle with AutoStart off, no effect on performance. The dealer wants to replace the module, battery. Everything (over 2k). I would like to know what part is actually failing and if there is a part number or any information since all my searches have come back with nothing. Thank you!

5 Replies

JACOBANDNICKOLAS

MECHANIC
109,747 POSTS

Hi,

The code you have, P0A9C, is an informational code. It doesn't provide specifics other than the battery pack control module (BPCM) has identified a problem within the hybrid circuit. In other words, there is an issue present and the BPCM is setting a light for someone to scan that module for issues. See pic 1 below.

What the dealership should have done (and they may have), is scan the battery pack control module (BPCM) for specific diagnostic codes. That will point us in the direction of the cause. By any chance, did they provide additional codes that may be related?

The two things you mentioned, either the battery or the module may be faulty. However, without knowing specifics, I can't confirm that. If the vehicle had lower mileage, then my first suspect would be the module. But at 120K, it could be the battery or other things.

I believe the module's OEM part number is 05057870AS. They aren't cheap.

Let me know.

Joe

See pic below.

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Wednesday, November 1st, 2023 AT 8:09 PM

BEACHCOWBOY

MEMBER
8 POSTS

Hi Joe. Thank you for your reply! I had forgotten to include the full notes. Looking back at the dealer notes, based on testing the conclusion is a failure of a temp sensor internal to the BPCM. Aka replace with part 68381513AA. Main question: is there a way to just replace a piece of the internals? Such as unsolder and solder in new temperature sensor components? Or am I in for the full $1,300 part?

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Thursday, November 2nd, 2023 AT 6:58 PM

JACOBANDNICKOLAS

MECHANIC
109,747 POSTS

Hi,

A dealership won't try to repair it. If it is a solder joint, it could be fixed, but you would need to find someone to do it. You may want to check online to see if there are any sites that provide remanufactured ones.

Interestingly, I went with one of my sons tonight to look at a new one just like yours. The electric end of it worries me. I guess it could be simply because of my age. LOL However, after reading an article about GM's plans to stop EV research and focus on hydrogen, I don't know which is worse. LOL No matter what, we make an imprint on the earth and atmosphere. I guess it's the least of the three evils.

Take care of yourself and let me know if you have questions or how things turn out.

Joe

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Thursday, November 2nd, 2023 AT 8:38 PM

BEACHCOWBOY

MEMBER
8 POSTS

Hi Joe,

I appreciate the reply :) I agree, this is technically my girlfriend's and when I found this issue I said "you bought a jeep with a hybrid part?" I'm used to my own inline 6.

But to the soldering. I'm comfortable with it (mechanical engineer and years of electrical) just haven't found anyone that has tried it. Worst case I buy the new one and figure out the cheap fix for everyone else to come.

Thanks for all,
Chris

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Friday, November 3rd, 2023 AT 3:35 PM

JACOBANDNICKOLAS

MECHANIC
109,747 POSTS

Hi,

It sounds like you know what you are doing. Just be careful around the battery. There is a lot of voltage present.

Let me know what you find.

Joe