Circuit Description
WARNING: This page is about a different car, the 2004 Pontiac Aztek and 2004 Buick Rendezvous. However, it is still accessible from the selected car via links, so may be relevant.
The theft deterrent control module sends the fuel enable password to the engine control module (ECM) via the serial data circuit. The ECM verifies the fuel enable password received matches the password stored in memory. If the fuel continue password is correct, the ECM enables the starting and fuel delivery systems. When replacing a ECM with a GM SPO replacement part, the new ECM will learn the incoming fuel enable password immediately upon receipt.