BCM Issues

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
Check the fifty amp fuse near the battery.

You can swap out the BCM with another one and relearn the key.
 
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

Goblin Guru
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.
 
Last edited:

Christopher Sanchez

Well-Known Member
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.
 

ctuinstra

Goblin Guru
Sorry guys, I meant to say "The 'Power steering' & 'Low Fuel' is when data is NOT being communicated ".
 
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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

Goblin Guru
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.
 
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?
 
So I finally have the kit to the starting point and it has the same issue before tear down. The security light comes on when I try to start it. Before I tried to start it everything seemed normal, the pump primed and the odb2 scanner read the codes. But when I tried to start it there was a large relay click in the fuse box area and the security light goes on. When it is this way the scanner can no longer even connect to the ecu. I tried the key relearn several times with nothing helping.
I am wondering if my best next step is to get a hptuner and disable the vats.
In afraid I'll either have to tow it to the dealer or buy all new ecu/bcm/TDM from another doner.
 

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ctuinstra

Goblin Guru
When you see the POWER STEERING, that is typically loss of communication. More specifically, loss if communication with the PS module, but still overall means loss if the serial data. Hard to say why it does it. It could be the ECM. I know I said I had one a while back and I’m glad I didn’t send it to you because it would have made things worse. I found out it’s an E67 and not a P12! Threw it in the trash.

I don’t think visabling VATS is going to help because you are getting a loss of communication. But I could be wrong. Also if you buy a HP Tuners license for that ECM and then find out it’s bad, you will have to buy another license for the new ECM.
 
I have somebody with a 2006 SS doing a part out that says they will ship the ECU/BCM/Ignition/TDM/Keys to me for $200.
Thinking that might be a good option to try, it was a running car so that should eliminate any issues with that stuff.
 
Unless there is a wiring issue that's causing the problem. Hate to be a downer, but it's a possibility.
It's possible. But I tried to check the wires as I went through the wiring harness.
I had a second BCM I just plugged in from when I tried to fix it awhile back and it still gives me the same power steering/low coolant light with that as well. Do you know what wire I might want to explicitly check for an open?
I got the guy to come down to $150 shipped for all the replacement parts, at this point it's almost worth $150 if nothing else to eliminate any of those components as an issue.
 

Ark :D

Goblin Guru
Check for continuity on both the tan and the tan/black wire, from OBDII to the ECM connector. Do this while the BCM is installed.

I'm not at my computer now so I can't easily tell you what pins it is in your connector, I'm sorry about that.
 
Check for continuity on both the tan and the tan/black wire, from OBDII to the ECM connector. Do this while the BCM is installed.

I'm not at my computer now so I can't easily tell you what pins it is in your connector, I'm sorry about that.
Ok I do have an update.
Colored me confused, but last week I tried to start it because it came up without the security light. As soon as I did I noticed a tiny spark in the tunnel and then it cut out and the security light came on. I took out my meter and I was showing 9v coming through the brake lines and it was grounding on a small spot where the powder coating didn't completely cover. I put something under it to keep it away, then kept checking random point to see where it was getting a charge from, I couldn't find anything but I did move stuff around checking everything I could think of. Now it no longer has a positive charge on the brake line for whatever reason.
So I tried to start it and it attempted but would crank very slow and then solenoid would start cycling and stop, after charging battery back up and checking all the connections I finally realized that the motor itself was barely grounded to the frame. So I grinded down the powder coating around one of the transmission bolts and then it finally cranked right over and started up.

Only catch is that it barely idles, it has some codes indicating the TPS has some issues the dash indicates reduced engine power and it is reading 100% accel position. It worked previously on the car so I am assuming I might have a wiring issue with it, I will have to begin tracking that down.

But I am excited to at least get it to the point the motor starts and runs at all.
 
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