B2603

CIRCUIT DESCRIPTION
The Body Control Module (BCM) controls the DRL relay by grounding the control circuit of the DRL relay coil.

CONDITIONS FOR RUNNING THE DTC
^ Voltage supplied to the module is in the normal operating voltage range (approximately 10 - 16 volts).
^ The DRL feature must be enabled.
^ The DRLs must be commanded ON.

CONDITIONS FOR SETTING THE DTC
^ The BCM detects a short to voltage in the control circuit of the DRL relay coil when the DRLs are ON.
^ The condition above must be present for more than 3 ms.

ACTION TAKEN WHEN THE DTC SETS
^ The BCM stores DTC B2603 in memory.
^ The SERVICE VEHICLE SOON telltale illuminates.

CONDITIONS FOR CLEARING THE DTC
^ A current DTC B2603 clears if the BCM no longer detects a short to voltage in the control circuit of the DRL relay coil.
^ A history DTC B2603 clears after 100 consecutive ignition cycles.
^ The BCM receives the Clear Code commend from the scan tool.

DIAGNOSTIC AIDS
^ If the DTC B2603 is a history DTC, the fault may be intermittent. Refer to Testing for Intermittent and Poor Connections in Diagrams.
^ An intermittent short to voltage in the following locations may cause an intermittent malfunction to occur:
- The control circuit of the DRL relay coil
- The DRL relay
- The BCM

TEST DESCRIPTION

Steps 1-13:

The number(s) below refer to the step number(s) on the diagnostic table.
2. Listen for an audible click when the DRL relay operates. Command both the ON and OFF states. Repeat the commands as necessary.
3. This step tests for voltage at the coil side of the DRL relay.
4. This step verifies that the Body Control Module (BCM) is providing ground to the DRL relay.
5. This step tests whether ground is constantly being applied to the DRL relay.
6. This step tests for a short to battery voltage