"U" Series

WARNING: This page does not describe the selected car, but rather 16 other vehicles, including the 2001 Pontiac Montana, 2001 Oldsmobile Silhouette, 2001 Oldsmobile Bravada, 2001 GMC Sonoma, and 2001 GMC Savana Special. However, it is still accessible from the selected car via links, so may be relevant.

Body Control Module (BCM) communicates through flashing FASTEN SEAT BELT indicator and sounding chime. Complete the following steps to enter diagnostic mode:

Turn ignition switch to OFF position.
Remove BCM PRGRM fuse (10-amp).
Turn ignition switch to ACC position. BCM first identifies what type of BCM is installed on vehicle by flashing fasten seat belts indicator and sounds chime 2, 3 or 4 times depending on what type of BCM is used on vehicle.
Turn ignition switch from ACC position to OFF position, and then back to ACC position within one second.

BCM will enter on-board diagnostic mode and flash FASTEN SEAT BELT indicator and sound chime equal to the number of DTCs stored in memory. If no DTCs are stored, BCM will not flash FASTEN SEAT BELT indicator or activate chime.

BCM flashes and sounds first DTC with lowest number, pauses, and then continues with next DTC until all DTCs are read. With DTC 1, BCM will only sound chime once, and FASTEN SEAT BELT indicator will not flash. Once all DTCs are read, BCM repeats sequence 3 times. If DTCs exist, perform appropriate test in accordance with DTC retrieved. See DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no DTCs exist, repair by symptom. See SYMPTOM INDEX table under SYSTEM TESTS.

To exit BCM diagnostic mode, perform the following:

Turn ignition switch to OFF position.
Reinstall BCM PRGRM fuse (10-amp).
Turn ignition switch to RUN position.