bad bcm?
09-24-2008, 07:27 AM
#1
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bad bcm? i have a 01 trans am. i came home from vacation and tried to start it but it wouldnt start. it cranks but nothin else. there is no spark or fuel. everything else seems to work fine, but the gages dont. and my friend tried to scan the computer but it said it was unable to communicate. he thinks its the body control module. he removed it and it was kinda hot. we didnt take the bcm apart yet, but does anyone know if this is right? or is there another problem we should check?
09-24-2008, 07:59 AM
#2
It's not the BCM. The BCM only affects starting as part of the VATS system. It disables the starter relay and turns on the security light on the dash when the wrong ignition key is used. Since you're not having trouble with the starter and you didn't mention the security light, it's safe to assume that the VATS system (and the BCM) isn't the source of your problem.
09-24-2008, 08:24 AM
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ive had the wires in my vats system break causing my car not to start randomly. I tried to pop the clutch to start it but would get killed immediately so I would suggest that as something to look at.
http://shbox.com/1/pass_key.html
Other than that, I have no idea.
http://shbox.com/1/pass_key.html
Other than that, I have no idea.
09-24-2008, 08:33 AM
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ok, when ur car wouldnt start would it make any noise or just be silent? thats what worries me when i had a problem w the vats before i would turn the key and it would just do nothing, got a new key and it was fine. but now its cranking. but if theres no spark or fuel it seems like is has to be something w the vats right?
09-24-2008, 09:48 AM
#7
Besides, there are literally dozens of reasons that the engine might not be getting spark or fuel - none of which have anything to do with the BCM. Your first step is to determine if the problem is spark or fuel (or something else). Then track down why. For example, there are fuses for the ignition, PCM, fuel injection, and engine control as well as relays for the fuel pump and ignition in junction block #2 under the hood. Have you checked those?
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09-24-2008, 03:18 PM
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i called speed inc, in schaumburg il. thats who did the cam and the other work on the car. he said he thought it was prob the computer. he said to swap it out w one from my friends cars and see if it works, if it does i need to get a new one and have it dyno tuned again. does that sound right to u? it kinda makes sense to me cuz the comp wont communicate. im not any kind of mechanic or anything but im assuming a mechanic can swap a comp pretty easily?
09-24-2008, 03:34 PM
#12
The PCM (Powertrain Control Module) is easy to remove and reinstall. You'll find it under the hood attached to the right fenderwell just in front of the firewall. It is easier to remove the PCM along with its bracket than to try to wiggle it out of the bracket while it's in the car. Use a 10mm socket to remove the two bolts holding the bracket, unplug the two large plugs, and pull it out.
Do this only for testing purposes and if you have a friend with an f-body similar enough to lend it to you. They differ by engine, transmission, rear axle ratio, and of course model year. 01 and 02 use the same PCM and 99-00 models should work well enough for just test starting the car.
Do this only for testing purposes and if you have a friend with an f-body similar enough to lend it to you. They differ by engine, transmission, rear axle ratio, and of course model year. 01 and 02 use the same PCM and 99-00 models should work well enough for just test starting the car.
