B1379

CIRCUIT DESCRIPTION
Ignition 3 input to the body control module BCM from the ignition switch, is used to determine the power mode the vehicle is in. When the BCM senses that the ignition 3 input is inactive when ignition 1 is active and the engine is running, DTC B1379 sets.

CONDITIONS FOR SETTING THE DTC
The ignition 3 input is inactive after the ignition 1 input has been active for 20 seconds.

CONDITIONS FOR RUNNING THE DTC
^ The engine is running.
^ At least 20 seconds has elapsed since the engine was started.

ACTION TAKEN WHEN THE DTC SETS
^ The SERVICE VEHICLE SOON indicator illuminates.
^ The check gages chime sounds.

CONDITIONS FOR CLEARING THE DTC
^ A current DTC B1379 will clear when the malfunction is no longer present and the ignition switch is cycled.
^ A history DTC clears when the module ignition cycle counter reaches the reset threshold, without a repeat of the malfunction.

DIAGNOSTIC AIDS
If the DTC is a history DTC, the problem may be intermittent. Perform the tests shown while wiggling the wiring and connectors. This can often cause the malfunction to appear.

TEST DESCRIPTION

Steps 1-5:

Steps 6-15:

The numbers listed below refer to the numbers on the diagnostic table.
4. This step determines if ignition 3 is shorted to ground.
5. This step determines if the BCM is internally shorted.
6. This step determines if the cruise control module is internally shorted.
7. This step determines if voltage is supplied from the battery to the fuse.