The service BCMs EEPROM chip must be programmed with the proper RPO configurations by using a scan tool. The EEPROM stores information regarding the vehicle options and point of sale. If the BCM is not properly configured with the correct RPO codes, the BCM will set default values for some systems, which could cause malfunctions in other systems. When the BCM is replaced, the BCM must be programed to identify the following information:

The BCM sends password information to the PCM on the serial data line to enable fuel for Vehicle Theft Deterrent (VTD) functions, therefore, the PCM must also be programmed to accept the new password sent by the BCM. The BCM programming procedure will enable the learn password mode for both the BCM and PCM. This mode allows the PCM to learn the new password sent by the BCM whenever the BCM or PCM is replaced. If the BCM and PCM are not properly programmed together, the vehicle will exhibit a no start condition and the PCM will store a DTC P1631.

When an ignition key or the BCM is replaced, the BCM must be programmed to accept the resistance value of the new or existing vehicle keys in order to allow PASS-Key® operation. Refer to Programming Theft Deterrent System Components in Theft Deterrents.

Important: After programming, perform the following to avoid future misdiagnosis:

1. Turn the ignition OFF for 10 seconds.
2. Connect the scan tool to the data link connector.
3. Turn the ignition ON with the engine OFF.
4. Use the scan tool in order to retrieve history DTCs from all modules.
5. Clear all history DTCs.