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