B2575

DTC B2575 Headlamp Control Circuit Malfunction:

CIRCUIT DESCRIPTION
This circuit controls the ALC relay coil by grounding the circuit through the body control module (BCM). This is a trouble code (both current and history) that indicates that the headlamps were not ON when the ALC relay output was ON.

CONDITIONS FOR SETTING THE DTC
Meet all of the following conditions:
^ The ALC option is enabled and ignition one is active.
^ The ALC headlamp output is active.
^ The high beams are not ON or are in DRL mode.
^ The low beams are OFF for five seconds.

ACTION TAKEN WHEN THE DTC SETS
^ Stores the DTC B2575 in the BCM memory.
^ The SERVICE VEHICLE SOON indicator will illuminate.

CONDITIONS FOR CLEARING THE DTC
^ The BCM reads the proper headlamp voltage.
^ Conditions for the fault are no longer present.
^ Use the scan tool.

DIAGNOSTIC AIDS
^ Use the following procedure in order to determine if the low beams function correctly:
1. Turn the ignition switch to the RUN position.
2. Cover the ambient light sensor on the dash.
3. Wait for 30 seconds. The low beams should illuminate.

^ Use the following procedure in order to determine if the high beams function correctly:
1. Turn the ignition switch to the RUN position.
2. Activate the high beams.
3. Cover the ambient light sensor on the dash.
4. Wait for 30 seconds. The high beams should illuminate.

TEST DESCRIPTION
The numbers below refer to the numbers on the diagnostic table.
4. This step determines if the body control module (BCM) verifies proper operation of the low beam headlamps.
6. This step determines if the BCM verifies proper operation of the high beam headlamps.