B2603

Diagnostic Chart:

Schematics:

CIRCUIT DESCRIPTION
The daytime running lamps (DRL) relay coil is controlled by the body control module (BCM). Positive voltage is applied to the relay coil through circuit 41. The BCM grounds circuit 592 in order to turn on the DRL relay. When circuit 592 becomes shorted to battery, DTC B2603 is set.

CONDITIONS FOR RUNNING THE DTC
^ The ignition switch is in the ON position.
^ The transaxle is not in the PARK position. The park brake is unapplied.
^ The DRL relay control is active (DRLs on).

CONDITIONS FOR SETTING THE DTC
CKT 592 is shorted to battery positive voltage for 1 second.

ACTION TAKEN WHEN THE DTC SETS
^ The BCM turns off the DRL relay control for the remainder of the ignition cycle.
^ The SERVICE VEHICLE SOON indicator illuminates.
^ The check gauges chime sounds.

CONDITIONS FOR CLEARING THE DTC
^ A current DTC B2603 will clear when the malfunction is no longer present and the ignition switch is cycled.
^ All the BCM history codes clear after 100 ignition cycles (from OFF to ON) with no current codes active during the 100 ignition cycles.

DIAGNOSTIC AIDS
^ DTC B2600 may also set along with this DTC.
^ If the DTC is a history DTC, the problem may be intermittent. Perform the tests while wiggling the wiring and connectors. This may often cause the malfunction to appear.

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 operates. Command both the ON and OFF states. Repeat the commands as necessary.
3. Tests for voltage at 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.