B2603

Diagnostic Chart:

CIRCUIT DESCRIPTION
The Body Control Module (BCM) controls the DRL relay. The BCM grounds the DRL relay coil control circuit, which in turns energizes the DRL relay.

CONDITIONS FOR RUNNING THE DTC
The BCM must be commanding the DRL relay to energize.

CONDITIONS FOR SETTING THE DTC
^ The BCM detects a short to battery in the DRL relay coil control circuit.
^ The condition above must be present for more than 0.3 seconds.

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 will clear if the BCM no longer detects a short to battery in the DRL relay coil control circuit.
^ A history DTC B2603 will clear after 100 consecutive ignition cycles if the condition for the malfunction is no longer present.

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

TEST DESCRIPTION
The number(s) below refer to the step number(s) on the diagnostic table.
2. Listen for an audible click when the DRL relay energizes. Command both the ON and OFF states. Repeat the commands as necessary.
3. Tests for voltage at the coil side of the DRL relay. The DRL/EXT lamps fuse supplies power to the coil side of the DRL relay.
4. Verifies that the Body Control Module is providing ground to the DRL relay.
5. Tests if ground is constantly being applied to the DRL relay.