Bricked BCM?

[rockola1971]

I don't believe a BCM would prevent the engine from starting, at least not in 99-02 trucks. I did V6 to V8 swap on my 99 Silverado and accidentally left my V6 fuseblock when I hooked up the battery back up. I damaged my cluster and BCM. I opened up the BCM and there was something fried inside and recall a burnt smell before I realized my mistake. But after swapping the V8 fuseblock, truck started just fine. I had to source another cluster and BCM from the junkyard and everything works good.

But I may wrong on the later trucks? I know the 03-06 wirings are very different.

BCM is where the passlock sends the resistance signal too and the BCM gives the PCM the go ahead allow engine start (notice I didnt say crank).

 

[strutaeng]

BCM is where the passlock sends the resistance signal too and the BCM gives the PCM the go ahead allow engine start (notice I didnt say crank).

Ok, that makes sense. I should have remembered that I had deleted VATS from my ECU. That's probably why my truck started.

 

[rilesnpsd]

BCM is where the passlock sends the resistance signal too and the BCM gives the PCM the go ahead allow engine start (notice I didnt say crank).

so you thinking its its bcm or passlock?

 

[rilesnpsd]

Figured it out! Wahooooo! It was a freakin fuse! 15 amp ecm fuse was blown. Not sure why but it was. It’s running! The beast lives!

 

[Joseph Garcia]

Thank you for posting the solution to your issue. Much appreciated.

Our collective knowledge base has been increased.

 

[rilesnpsd]

pulled all codes.. bunch of u1000 codes and a few b codes.. I thought its like the computer isn't talking to anything..
Sure enough. A dollar fuse saved me hundreds.

 

[rockola1971]

so you thinking its its bcm or passlock?

At the time he stated he didnt think the BCM would keep engine from starting. It actually will. The Passlock system includes the BCM and if the BCM were bricked or anything defective related to it including fuse, wiring and its grounds then it would indeed keep the engine from running. Typically though when the problem is passlock related the engine will start and run for 3secs or so then shut off immediately. Passlock kills the fuel pump power if I remember correctly. Now I dont know if a totally bricked or Defective BCM will keep an engine from starting at all. Ive never come across that bridge luckily.

 

[BlackBearPerf]

Figured it out! Wahooooo! It was a freakin fuse! 15 amp ecm fuse was blown. Not sure why but it was. It’s running! The beast lives!

That is great to hear!