B3128

DTC B3128

CIRCUIT DESCRIPTION




The body control module (BCM) controls the driver door unlock relay. Voltage is applied to the driver door unlock relay through the driver door unlock relay control circuit when the BCM senses a door unlock switch activation or a keyless entry unlock command.

CONDITIONS FOR RUNNING THE DTC
Battery positive voltage is between 9 and 16 volts.

CONDITIONS FOR SETTING THE DTC
- The BCM detects an open in the driver door unlock relay control. This condition must be present for more than 0.3 seconds.
- The BCM detects a short to ground in the driver door unlock relay control while commanding the driver door unlock relay. This condition must be present for more than 0.3 seconds.

ACTION TAKEN WHEN THE DTC SETS
- The driver door unlock relay will be inoperative.
- The BCM stores either DTC B3127 or DTC B3128 in memory.

CONDITIONS FOR CLEARING THE DTC
- A history DTC will clear after 100 consecutive fault free ignition cycles.
- A scan tool may be used to clear the DTC.

DIAGNOSTIC AIDS
- The following conditions may cause the DTC to set:
- An open or short to ground in the driver door unlock relay control circuit
- The a faulty driver door unlock relay
- The BCM is shorted to ground internally.
- If the DTC's are a history DTC, the fault may be intermittent.

TEST DESCRIPTION

Steps 1-12:

The numbers below refer to the step numbers on the diagnostic table.
2. Listen for an audible noise when the driver door unlock relay is commanded. Command the door locks to lock and unlock. Repeat the commands as necessary.
3. Verifies that the BCM is providing voltage to the driver door unlock relay.
4. Tests for an open in the driver door unlock relay ground circuit.