Codes b124b and B1325?

HONEYBOBO

MEMBER
2016 CHEVROLET SILVERADO
5.3L
V8
2WD
AUTOMATIC
95,000 MILES

I did all the basics load test the battery check for good battery, connection, and not any problems except having a slight hesitation at hard throttle and a problem with getting a Bluetooth connection. I found the service bulletin for this problem and started doing a voltage drop test on the battery cables, but they all seemed okay but I really need a wiring diagram for the body control module and a pin out. And maybe there’s a flow chart to trace this problem being an open circuit and having a service bulletin. This seems to be a very common problem.

11 Replies

KEN L

MASTER CERTIFIED MECHANIC
48,323 POSTS

Yep, it sounds like the BCM has gone out which is common, but here are the wiring diagrams so you can see how the system works and check the grounds and power inputs to confirm the failure. I would also check the 8 BCM power fuses which as in the wiring diagrams as well.

Code B124B pertains to the rear defogger relay control circuit. This issue is discussed in TSB 17-NA-345

Code B1325 relates to control module power circuit low/high voltage. This issue is addressed in TSB 18-NA-161

This guide can help:

https://www.2carpros.com/articles/how-to-check-wiring

Check out the images (below). Please upload pictures or videos in your response of any problems so we can see what to help you with.

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Wednesday, December 11th, 2024 AT 11:21 AM

HONEYBOBO

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Thanks for fast response, I have gone over the things I have found from service bulletin and checked My battery cables, and they are all good. I added a ground strap to the body and cleaned the ones that I found. I had to replace the starter after doing voltage load test on cables. I guess it was on its way out, I have been doing a lot of research, and I ran across this service bulletin, check it out bulletin:
NO :Pic5910c I’ll send pic , another question, how hard is it to get to the ground location for BCM that is supposed to be right below the driver side pillar, do you have to pull the instrument cluster or is there another way to get around all that?I just want to get to the bottom of this as quick as possible because, if it needs a body control module, I may just sell the truck the way it is after I find out how much it’s going to cost to have one programmed and the cost of one. Also, the USB connector in the center console is not connected so that must be my open circuit and I want to know if there is a way to bypass that or do I have to find a replacement And by looking at the center console there does not look like there is any way to open it up to get to USB plug. I’ll start going over all this info you sent me and get back to you, let me see if I can send you that bulletin I found I’m going to go fire up my printer. Thanks

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Wednesday, December 11th, 2024 AT 6:33 PM

HONEYBOBO

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I just started looking at the diagram and I do not see how to reference the connectors (there is plug color key) each plug had different color and I do not see where to figure out how to read it really confusing, where do I need to look?
Thanks

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Wednesday, December 11th, 2024 AT 6:58 PM

HONEYBOBO

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Now that I’m looking at it looks like this the PCM maybe anyway get back with me on this. Thanks

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Wednesday, December 11th, 2024 AT 7:18 PM

KEN L

MASTER CERTIFIED MECHANIC
48,323 POSTS

Wiring diagrams are like road maps, just follow the wires and they say what they do. If the wiring has not been tampered with, I would try the reprogrammed BCM.