Powertrain Control Module
WARNING: This page is about a different car, the 2002 GMC Savana, 2002 Chevrolet Chevy Express, 2001 GMC Savana, and 2001 Chevrolet Chevy Express. However, it is still accessible from the selected car via links, so may be relevant.
Powertrain Control Module (PCM) contains the remainder of the logic of theft deterrent system. If a class 2 message containing a valid password is received from Passlock(tm) module, PCM will continue to allow fuel injectors to operate. PCM will allow fuel injectors to operate until it decides there is no valid password coming from Passlock(tm) module. If PCM does not receive a class 2 message, or receives a class 2 message with an incorrect password, engine will crank and will not run or will start and stall immediately.