B1440
CIRCUIT DESCRIPTIONThe body control module (BCM) monitors the Ignition 0, Ignition 1 and the Accessory signals from the ignition switch. The BCM uses the voltage state (B+ or 0) and the sequence of state changes to determine the power mode called for by the ignition switch.
CONDITIONS FOR RUNNING THE DTC
The BCM must be powered and must detect a change in the ignition switch circuit states.
CONDITIONS FOR SETTING THE DTC
^ One of the ignition switch circuits may be shorted to either B+ or ground.
^ The sequence of the change of the circuit is incorrect for the expected power mode.
ACTION TAKEN WHEN THE DTC SETS
^ The BCM stores the DTC B1440 to memory.
^ The BCM operates in a fail-safe power mode dependent on the last valid power mode detected and the state of the engine run flag data on the class 2 serial data communications circuits.
^ The other modules on the vehicle operate in a fail safe power mode dependent on the last valid power mode transmitted by the BCM and the state of the engine run flag on the class 2 serial data communications circuits.
CONDITIONS FOR CLEARING THE DTC
^ A current DTC clears when the malfunction is no longer present.
^ A history DTC clears when the module ignition cycle counter reaches the reset threshold, without a repeat of the malfunction.
TEST
Steps 1-8:
Steps 9-15:
