Expert or Certified Tech help need
Thread Starter
8th Gear
Joined: Nov 2006
Posts: 8
Likes: 1
From: Dallas Texas
Expert or Certified Tech help need
I have an issue with a 1997 LS1 corvette motor that has been transplated into another car. The original PCM was used and BCM left out.
The motor starts/runs then dies in 2-3sec. The VATS has been disabled. Now the strange part! When I use a scan tool to connect to the PCM the engine starts and runs fine. No engine DTCs thrown. The automatic tranny codes have been disabled via EFIlive. I have tried many times and verified the engine will only run with a scan tool connected to the PCM. This leads me to believe this PCM requires a serial data connection in order to run. Does anyone know if this is the case. If so is there a work around without installing a BCM?
The motor starts/runs then dies in 2-3sec. The VATS has been disabled. Now the strange part! When I use a scan tool to connect to the PCM the engine starts and runs fine. No engine DTCs thrown. The automatic tranny codes have been disabled via EFIlive. I have tried many times and verified the engine will only run with a scan tool connected to the PCM. This leads me to believe this PCM requires a serial data connection in order to run. Does anyone know if this is the case. If so is there a work around without installing a BCM?
Safety Car
Joined: Aug 2000
Posts: 4,933
Likes: 30
From: San Rafael CA
At engine start the BCM sends a password to the PCM indicating that it is "happy" with the VATS (pellet) and some other tests it performs. Once the PCM receives the password the PCM and BCM agree on a new password to be used the next time the engine is started. This is done to prevent a car being stolen by swapping out a PCM and/or BCM ... they have to "match". When the PCM doesn't get a valid password, it shuts the engine down.
There are other interactions at start up, such as the SDM testing for a VIN match in the PCM, and also testing for a PROM ID match with the BCM.
You'll need someone with a really good understanding of the interaction between the car's modules to help you run a PCM alone.
Good luck.
There are other interactions at start up, such as the SDM testing for a VIN match in the PCM, and also testing for a PROM ID match with the BCM.
You'll need someone with a really good understanding of the interaction between the car's modules to help you run a PCM alone.
Good luck.
Last edited by BlackZ06; Dec 14, 2006 at 02:27 AM.
