B1379

DTC B1379

CIRCUIT DESCRIPTION
The body control module (BCM) uses the ignition 0, ignition 1, and ignition 3 inputs to determine the power mode of the vehicle. The BCM may store a DTC if it detects an invalid combination of ignition input signals. When the BCM senses that the ignition 1 input is active and ignition 3 is inactive while the engine is running, DTC B1379 sets.

DTC DESCRIPTOR
This diagnostic procedure supports the following DTC:
DTC B1379 Device Ignition 3 (ON) Circuit Open

CONDITIONS FOR RUNNING THE DTC
The engine has been running for at least 20 seconds.

CONDITIONS FOR SETTING THE DTC
The ignition 1 input is active and ignition 3 is inactive

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 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 1-13:

Steps 14-16:

The numbers below refer to the step 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.