GM Service Manual: 98-02 F-Body Installation + New BCM Programming

car diagnostic tool

Same installation procedure for all 98-02 F-bodies. The GM service manual is quite specific on the procedure:

Quote:

Body Control Module (BCM) Programming/RPO Configuration

Important

Any new body control module (BCM) will automatically program to the resistance of the key (or interrogator setting) being used at the first ignition ON cycle. This can only be done once for the life of the module.

A new BCM is not programmed. Before the system will function properly it must be programmed to the code that matches the customer’s keys.

  1. Install the new BCM. Refer to Body Control Module Replacement
  2. Insert one of the customer’s keys into the ignition cylinder and turn it to the on position. Its good to start the engine at this time to verify system operation.
  3. Observe the SECURITY indicator lamp for the following:

– The indicator lamp lights for approximately 5 seconds and then goes out. This indicates that the BCM is programmed properly.

– The indicator lamp flashes at a rate of one flash per second until the ignition is off. This indicates that the BCM did not program and the system components, wiring and contacts should be checked for a fault.

BCM doesn’t even connect to a Tech 2 programmer for diagnostics let alone programming. BCM Diagnostics are done in the car using the SECURITY light in the instrument cluster to flash diagnostic codes:

Quote:

Perform the following steps to enter the BCM diagnostic mode:

– Turn the ignition switch to the RUN position.

– Turn the ignition switch to the OFF position.

– Remove the Radio fuse 17 from the I/P fuse block.

– Turn the ignition switch to the ACCY position (the BCM sounds 1 or 2 audible warning tones).

– Within five seconds, turn the ignition switch to the OFF position and immediately (within 1 second) back to the ACCY position (the BCM sounds three audible warning tones to signal entry into the diagnostic mode).

The BCM will begin flashing trouble codes four seconds after entering the diagnostic mode. Each flash of the security indicator lamp on the IPC represents a number. For example, one flash followed by two quick flashes represents code 12. Each code is displayed three times before the next code is displayed. Stored DTCs are displayed in numerical order. Once the last code is displayed, the list begins again with the first code. The display continues until the diagnostic mode is exited