B2575

DTC B2575

CIRCUIT DESCRIPTION
The body control module (BCM) turns on the LOW BEAM relay when the ambient light sensor senses a dark condition or the low beam headlamps are requested ON. Battery positive voltage is supplied to the LOW BEAM relay at all times. The BCM grounds the LOW BEAM relay control circuit in order to activate the relay.

DTC DESCRIPTOR
This diagnostic procedure supports the following DTC:
DTC B2575 Headlamp Control Circuit

CONDITIONS FOR RUNNING THE DTC
- The ignition switch is in the ON position.
- The ambient light sensor senses a dark condition, automatic lamp control (ALC) headlamps ON.

CONDITIONS FOR SETTING THE DTC
- B2575.01 will set if there is a short to voltage in the low beam relay control circuit.
- B2575.06 will set if there is an open or short to ground in the low beam relay control circuit.

ACTION TAKEN WHEN THE DTC SETS
- The SERVICE indicator illuminates.
- The check gages chime sounds.

CONDITIONS FOR CLEARING THE DTC
- The conditions for setting the DTC are no longer present.
- A history DTC clears after 100 malfunction-free ignition cycles.
- The BCM receives the clear code command from the scan tool.

DIAGNOSTIC AIDS
- Turn the ignition switch to the OFF position, cover the ambient light sensor on the dash, wait for 15 seconds, and then return the ignition to the ON position. The low beam headlamps should illuminate.
- If the DTC is a history DTC, the problem may be intermittent.

TEST DESCRIPTION

Step 1 - Step 13:

The numbers below refer to the step numbers on the diagnostic table.
2. Listen for an audible click when the LOW BEAM relay operates. Command both the ON and OFF states. Repeat the commands as necessary.
4. This step tests for voltage at the coil side of the LOW BEAM relay.