koolaid91

Okay, just joined this group and this is my first post so I hope I posted in the right place. I'm hoping someone can help me out. I have a 2005 lsj and I just had a Gm performance clutch and fidanza lightweight flywheel installed. During the process of unhooking everything my buddy forgot to unhook the battery and only unhooked the positive jump terminal under the hood, it arched off the pcm. I was hoping to god it didn't fry anything. After everything was installed and hooked back up I go to start her up and my security light is on. Tried the whole relearn process and it won't work, the light never goes out. I work at a chevy dealer so I had a tech hook up the tech 2, he said that the pcm wasn't communicating so I ordered a zzp 1.0 pcm. I installed the pcm and still can't get the relearn to work. Here is where it gets weird, I starting trying a few different things and attempted to start the vehicle with the trans in reverse. When I turn the key nothing happens but when I go to turn the key backwards into the first position the starter engages and the vehicle tries to start. Nobody seems to be able to tell me what may be going on. Any input would be greatly appreciated.

rchiwawa

I am guessing you have access to the white papers I would need about how starting is done on these cars that I would need to look at in order to help. My guess is that starting is computer controlled and not "dumb" in the sense that the key position makes an electro-mechanical circuit connection to initiate the starter motor nad all starting related processes and that it is very, very confused.

To put my lack of low level, systemic understanding into perspective, I had no idea that the turn signals were purely IC controlled on my CObalt and had to be told by a coworker that my brake light was out since the timing on the turn signal was normal and as far as I was concerned, no fillaments were toasted. SInce then I do a monthly check on my lighting. I might shoot an email to GM engineering if I were you since the synptoms of your mode of failure are at the very least interesting and would probably pique someone's curiosity.

Celestial739

Did you check fuses to start? Make sure none blew.. and as far as security I'm pretty sure the BCM stores your security data, if fuses are fine you probably have a communication issue, likely wiring or pin connection since you've tried a new PCM already, double check any connectors you may have had unplugged for corrosion/bent pins.. strange it cranks when turning key back, probably won't start because BCM isn't getting correct signal from your key, hence the security light, it won't enable fuel/spark

koolaid91

I check all the fuses and they all seem to be fine, I'll check all the connections again and make sure there isn't any bent pins or anything like that. I haven't hooked up the tech 2 to see if the new pcm is communicating so I'll make sure of that as well. Hopefully the BCM isn't screwed up to.