How to test the battery control module?

Tiny
STEVE620
  • MEMBER
  • 2007 GMC ENVOY
  • 4.2L
  • 6 CYL
  • 4WD
  • AUTOMATIC
  • 110,469 MILES
Every now and then the battery light goes on, what I found was If I disconnect the battery control module then plug it back in, then restart engine the battery light goes off. Is there a way to test battery control module? (It is connected to the negative side of the battery.)
Thursday, September 22nd, 2022 AT 9:53 AM

3 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,700 POSTS
Hi,

The testing of the module can be done, but there are multiple tests based on different diagnostic trouble codes. I'm not sure which diagnostics to provide without a code.

Here is what needs to be done: Have the can-bus scanned for codes. CAN stands for controller area network. Basically, the different computers/modules are tied together via a few wires. If there is a code stored, this type of scan will retrieve it regardless of the module storing it.

Here is a link that explains how it's done. Also, I do recommend doing this when the light is turned back on.

https://www.2carpros.com/articles/can-scan-controller-area-network-easy

I have one other question. Once the battery is disconnected and the light goes out, how long does it take for it to turn back on? Does it seem like a consistent amount of time?

Let me know.

Joe
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Thursday, September 22nd, 2022 AT 9:10 PM
Tiny
STEVE620
  • MEMBER
  • 64 POSTS
There are no codes coming up, only the light on dash. This is the third time it has come on in about 3 months. I have a Bluedriver scan tool.
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Friday, September 23rd, 2022 AT 1:57 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,700 POSTS
Hi,

I'm not familiar with the scanner you mentioned. When the light comes on, do the lights dim or does anything seem to slow down?

If you haven't already, let's check to see if the alternator is doing the job. When the light comes on, that would be a perfect time.

Here is a link that explains how to do it:

https://www.2carpros.com/articles/how-to-check-a-car-alternator

Also, is the scan tool you have able to read all codes?

Let me know.

Joe
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Friday, September 23rd, 2022 AT 7:56 PM

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