Help - bcm
10-19-2021, 08:07 AM
#1
Teching In
Thread Starter
Help - bcm New to owning a LS1 (2000 WS6), but recently, my car had been running fine, then out of the blue one day, I started it, and it ran for about 5 seconds, then shut off, like the fuel is being shut down. It always starts fine, then just shuts down. Everything else works on the car electronically. The shop is telling me that the BCM is bad and is not recognizing the key chip. Is this something that happens, and also, is there a remedy. The shop is telling me that the BCM's for this car are no longer made, so what are my options? Thank you in advance for any insight.
10-20-2021, 09:20 AM
#2
Your shop is referring to VATS - Vehicle Anti-Theft System - which is contained in the BCM (Body Control Module). VATS disables the fuel enable signal to the prevent the car from running which would cause symptoms as you describe. But it would also disable the starter relay causing the engine not to crank in the first place and it illuminates the SECURITY light in the instrument panel (which you didn't mention).
Now, if it is a VATS problem then you have other options besides replacing the BCM. The PCM (Powertrain Control Module) can be programmed to ignore the lack of a fuel enable signal but that could be an expensive solution if you're not planning other performance mods which require additional programming anyway.
It could be something as simple as dirt and grime on the key resistor pellet and/or inside the ignition cylinder. You can try a spare ignition key if you have one or clean the key pellet contacts with a pencil eraser followed by rubbing alcohol. The ignition cylinder can be cleaned with spray electronic cleaner and a cotton swab or pipe cleaner.
If that doesn't work and you still suspect that VATS is the problem then you can do a VATS bypass. There are plenty of threads in this forum on how to do a bypass... a search for VATS bypass will get lots of results. There are 15 different resistor values used for VATS by GM (actually only 14 of them were used in f-bodies but that doesn't help much). Start by measuring the resistance of your existing key and selecting the value which most closely matches. If that doesn't work then you may have to go through the other values one by one until you find the one that works. There are kits you can buy which have all the possible resistor values included - some even have a box with a simple **** to make selection easy.
I would try those things before I'd even consider replacing the BCM. GM has discontinued the original BCM but there are places that sell refurbished ones. I even saw them on Amazon a while ago.
Now, if it is a VATS problem then you have other options besides replacing the BCM. The PCM (Powertrain Control Module) can be programmed to ignore the lack of a fuel enable signal but that could be an expensive solution if you're not planning other performance mods which require additional programming anyway.
It could be something as simple as dirt and grime on the key resistor pellet and/or inside the ignition cylinder. You can try a spare ignition key if you have one or clean the key pellet contacts with a pencil eraser followed by rubbing alcohol. The ignition cylinder can be cleaned with spray electronic cleaner and a cotton swab or pipe cleaner.
If that doesn't work and you still suspect that VATS is the problem then you can do a VATS bypass. There are plenty of threads in this forum on how to do a bypass... a search for VATS bypass will get lots of results. There are 15 different resistor values used for VATS by GM (actually only 14 of them were used in f-bodies but that doesn't help much). Start by measuring the resistance of your existing key and selecting the value which most closely matches. If that doesn't work then you may have to go through the other values one by one until you find the one that works. There are kits you can buy which have all the possible resistor values included - some even have a box with a simple **** to make selection easy.
I would try those things before I'd even consider replacing the BCM. GM has discontinued the original BCM but there are places that sell refurbished ones. I even saw them on Amazon a while ago.
10-20-2021, 02:06 PM
#3
Teching In
Thread Starter
Your shop is referring to VATS - Vehicle Anti-Theft System - which is contained in the BCM (Body Control Module). VATS disables the fuel enable signal to the prevent the car from running which would cause symptoms as you describe. But it would also disable the starter relay causing the engine not to crank in the first place and it illuminates the SECURITY light in the instrument panel (which you didn't mention).
Now, if it is a VATS problem then you have other options besides replacing the BCM. The PCM (Powertrain Control Module) can be programmed to ignore the lack of a fuel enable signal but that could be an expensive solution if you're not planning other performance mods which require additional programming anyway.
It could be something as simple as dirt and grime on the key resistor pellet and/or inside the ignition cylinder. You can try a spare ignition key if you have one or clean the key pellet contacts with a pencil eraser followed by rubbing alcohol. The ignition cylinder can be cleaned with spray electronic cleaner and a cotton swab or pipe cleaner.
If that doesn't work and you still suspect that VATS is the problem then you can do a VATS bypass. There are plenty of threads in this forum on how to do a bypass... a search for VATS bypass will get lots of results. There are 15 different resistor values used for VATS by GM (actually only 14 of them were used in f-bodies but that doesn't help much). Start by measuring the resistance of your existing key and selecting the value which most closely matches. If that doesn't work then you may have to go through the other values one by one until you find the one that works. There are kits you can buy which have all the possible resistor values included - some even have a box with a simple **** to make selection easy.
I would try those things before I'd even consider replacing the BCM. GM has discontinued the original BCM but there are places that sell refurbished ones. I even saw them on Amazon a while ago.
Now, if it is a VATS problem then you have other options besides replacing the BCM. The PCM (Powertrain Control Module) can be programmed to ignore the lack of a fuel enable signal but that could be an expensive solution if you're not planning other performance mods which require additional programming anyway.
It could be something as simple as dirt and grime on the key resistor pellet and/or inside the ignition cylinder. You can try a spare ignition key if you have one or clean the key pellet contacts with a pencil eraser followed by rubbing alcohol. The ignition cylinder can be cleaned with spray electronic cleaner and a cotton swab or pipe cleaner.
If that doesn't work and you still suspect that VATS is the problem then you can do a VATS bypass. There are plenty of threads in this forum on how to do a bypass... a search for VATS bypass will get lots of results. There are 15 different resistor values used for VATS by GM (actually only 14 of them were used in f-bodies but that doesn't help much). Start by measuring the resistance of your existing key and selecting the value which most closely matches. If that doesn't work then you may have to go through the other values one by one until you find the one that works. There are kits you can buy which have all the possible resistor values included - some even have a box with a simple **** to make selection easy.
I would try those things before I'd even consider replacing the BCM. GM has discontinued the original BCM but there are places that sell refurbished ones. I even saw them on Amazon a while ago.