B2600

Diagnostic Chart 1:

Diagnostic Chart 2:

Schematic:

CIRCUIT DESCRIPTION
The daytime running lamps (DRL) are controlled by the body control module (BCM). The BCM grounds the DRL relay control circuit in order to energize the DRL relay coil. This action places both low and high beam headlamps in series with each other with the DRL relay terminal 87 providing the ground and the RT HDLP fuse providing battery positive voltage. The BCM monitors the low and high beam circuits to ensure that the DRLs are operating properly. If the BCM senses that the DRLs are not operating properly, DTC B2600 is set.

CONDITIONS FOR RUNNING THE DTCs
The headlamp switch is off.
^ The park brake is unapplied.
^ The transaxle is in gear.

CONDITIONS FOR SETTING THE DTC
One or more of the following conditions is/are present:
^ The DRL relay control circuit is open.
^ The DRL relay output circuit is open. The right headlamp power teed circuit is open.
^ The left headlamp power feed circuit is open.
^ The DRL relay ground circuit is open.

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 indicators lights

CONDITIONS FOR CLEARING THE DTC
A current DTC B2600 clears when the malfunction is no longer present and the ignition switch is cycled.
^ All BCM history codes clear after 100 ignition cycles (from OFF to ON) with no current codes active during the 100 ignition cycles.

DIAGNOSTIC AIDS
^ Diagnose all other DRL DTCs before DTC B2600.
^ If the DTC is a history DTC, the problem may be intermittent. Perform the above 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.
4. Listen for an audible click when the DRL relay operates. Command both the ON and OFF states. Repeat the commands as necessary.
5. Tests for voltage at the coil side of the DRL relay.
6. Verifies that the body control module is providing ground to the DRL relay.