Hey try this came from brian1
he has a class 2 communication problem, here is how to check. You have to start by disconnecting each module 1 at a time, when you disconnect the IPC, turn the key on and use the tech 2 and see if you can communicate with class 2, if you can go to the next module, ECM disconnect it see if you can communicate with class 2, if you can go to the next module, keep doing that to each module and the last one disconnected is the one that is to be replaced, also Test the DLC ground circuit terminal 5 for a high resistance or an open. Also Disconnect the Fuse Block-Left I/P connectors that contain the Class 2 serial data circuits. Disconnect the connector containing the Class 2 serial data circuit from the BCM module. Inspect Fuse Block-Left I/P connectors at the terminals containing the Class 2 serial data circuits for poor connections/terminal tension. Test for an open circuit between pin 2 on the DLC connector and the harness connector of the Fuse Block-Left I/P. Test the Class 2 serial data circuit for a short to B+ or a short to ground between the mating connectors terminals integrated into the Fuse Block-Left I/P, that contain the Class 2 serial data circuits. All the modules will be listed with the tech 2, class 2 is sometimes a pain in the exhaust to diagnose.
Monday, August 10th, 2009 AT 9:52 AM