B1477

DTC B1477

CIRCUIT DESCRIPTION
The BCM interfaces with the vehicle's power distribution system through the WND RAP relay. The WND RAP relay allows the BCM to control the application of power to the feed circuits of the Power Windows. When the ignition switch is in either the ACC or the ON position, the BCM energizes the WND RAP relay by providing B(+) to the WND RAP relay control circuit.

The BCM turns off the WND RAP relay when the ignition switch is in the START position. The RAP feature therefore disables during engine cranking.

When the ignition switch turns from ON or ACC to OFF, with all of the vehicle doors closed, the BCM leaves the WND RAP relay energized for 10 minutes, or until any vehicle door opens.

CONDITIONS FOR RUNNING THE DTC
The system voltage must be between 9-16 volts.

CONDITIONS FOR SETTING THE DTC
- The BCM detects a short to ground in the WND RAP relay control circuit when the BCM is trying to energize the WND RAP relay.
- The condition above must be present for more than 1 second.

ACTION TAKEN WHEN THE DTC SETS
- The BCM stores DTC B1477 in memory.
- The circuits powered by the WND RAP relay will not operate.

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.

DIAGNOSTIC AIDS
If the DTC B1477 or B1478 is a history DTC, the fault may be intermittent.

The following conditions may cause an intermittent malfunction to occur:
- An intermittent short to ground or to battery in the WND RAP relay control circuit.
- The WND RAP relay coil is shorted to ground or to battery internally.
- The BCM is shorted to ground or to battery internally.

TEST DESCRIPTION

Steps 1-4:

Steps 5-10:

The numbers below refer to the step numbers on the diagnostic table.
2. During the WND RAP relay operation, listen for an audible click. Command the ON and the OFF states. Repeat the commands as necessary.
3. Verifies whether the WND RAP relay has a defect.
4. Tests the control circuit of the WND RAP relay.
5. Tests the ground circuit of the WND RAP relay.