Diagnostic Functions: Programming

The central electronic module (CEM), engine control module (ECM), keyless vehicle module (KVM) (cars with the keyless entry system only) and steering column lock module (SCL) are linked together by codes to increase the security of the immobilizer system. Codes must be programmed in when replacing a control module in order for the vehicle to be started. The serial number of the brake control module (BCM) is also checked by the engine control module (ECM) before it allows the engine to be started. The serial number of the brake control module (BCM) must be entered into the engine control module (ECM) if the brake control module (BCM) or engine control module (ECM) are replaced. This occurs automatically when downloading software into the new control module.