BCM Issues

#1
So I picked up a 07 SS SC from copart a few months ago to prepare for my spring build. It was a running and driving car, I drove it home myself. However being a wrecker car it didn't have a good battery. A few weeks ago when I went to jump it to move it again I wasn't paying attention and made a dumb mistake of hooking it up backwards.

Now it won't start, I have check all the fuses twice. I get a check engine and security light and when I try to start, I hear a relay but nothing happens. At one point the display was saying 'Power steering' & 'Low Fuel' but not anymore. I think its a solid guess that the BCM is toast. And it looks like to replace the BCM I would have the partially disassembled car towed to the dealer to have a new one programmed to the ecu. It seems cheaper however to find a ecu and bcm pair from a yard (plus keys?) and just swap them both, or would that even work?

I would probably prefer to get this resolved before I fully tear apart the car and assemble the kit, I am not sure if I have to end up take it in to the dealer for reprogramming that they would even work on the kit car.

Thanks for any info or suggestions since I am new to the GM platform.
 

Lonny

Administrator
Staff member
#2
Check the fifty amp fuse near the battery.

You can swap out the BCM with another one and relearn the key.
 
#3
Check the fifty amp fuse near the battery.

You can swap out the BCM with another one and relearn the key.
I have tested that fuse as well.

I have read about the key relearn but I was under the impression that you have to reprogram a replacement BCM with a tech 2 to match your ECU.
Is that incorrect?

Thank you.
 

ctuinstra

Well-Known Member
#5
The 'Power steering' & 'Low Fuel' is when data is NOT being communicated. I had this exact same thing when HP Tuners locked up my ECM. I know this doesn't help you much other than a little understanding. This is why Lonny had you check the fuse to see if there was no power to the BCM (hence lack of communication). But if that is good, and there are no other blown fuses, your BCM is probably bad (if not the ECM and PS controller).

I have an ECM for that car that I bought but never needed to use if that would help.
 
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#6
So I picked up a 07 SS SC from copart a few months ago to prepare for my spring build. It was a running and driving car, I drove it home myself. However being a wrecker car it didn't have a good battery. A few weeks ago when I went to jump it to move it again I wasn't paying attention and made a dumb mistake of hooking it up backwards.

Now it won't start, I have check all the fuses twice. I get a check engine and security light and when I try to start, I hear a relay but nothing happens. At one point the display was saying 'Power steering' & 'Low Fuel' but not anymore. I think its a solid guess that the BCM is toast. And it looks like to replace the BCM I would have the partially disassembled car towed to the dealer to have a new one programmed to the ecu. It seems cheaper however to find a ecu and bcm pair from a yard (plus keys?) and just swap them both, or would that even work?

I would probably prefer to get this resolved before I fully tear apart the car and assemble the kit, I am not sure if I have to end up take it in to the dealer for reprogramming that they would even work on the kit car.

Thanks for any info or suggestions since I am new to the GM platform.
I would check the Main fuse box for the smell of burnt plastic, I also made a dumb mistake trying to jump the starter, cost me $230 replaced the fuse box and problem solved. I had the same issues with the info center not displaying "low fuel and power steering" like it was before. but there was a strong smell of burnt plastic from the main fuse box that cant be missed.
 
#8
I bought a BCM from a wreckers and and I get the same behavior. I might have to look at replacing the ECU and give that a shot if nothing else then to start knocking things off the list to narrow it down.
 

ctuinstra

Well-Known Member
#9
I have an ECM for that exact car sitting on the shelf. If you want to pay for shipping, you are free to try it to see if it helps. Granted it’s not married to the BCM but might give more info. If it works for you and you can get it married, I only paid like $20 for it.
 
#10
I have an ECM for that exact car sitting on the shelf. If you want to pay for shipping, you are free to try it to see if it helps. Granted it’s not married to the BCM but might give more info. If it works for you and you can get it married, I only paid like $20 for it.
What does it take to pair it to the ECM does it need a dealer tool?