B2600

DTC B2600

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 provides a path to ground for the RH and LH headlamps through the DRL relay and the DRL resistor. The DRL resistor reduces the intensity of the low beam headlamps for DRL operation. The BCM monitors the low beam circuit to ensure that the DRL are operating properly.

DTC DESCRIPTOR
This diagnostic procedure supports the following DTC:
DTC B2600 Daytime Running Lamp Control Circuit

CONDITIONS FOR RUNNING THE DTCs
- The ignition switch is in the RUN position.
- The headlamp switch is in the AUTO position.
- The park brake is not applied.
- The gear selector is not in the PARK position.

CONDITIONS FOR SETTING THE DTC
Any of the following conditions will set this DTC:
- The DRL resistor supply voltage circuit is open, or shorted to ground.
- The headlamp low beam signal circuit between a headlamp and the underhood fuse block is open or shorted to ground.
- The battery positive voltage circuit to the headlamp is open or shorted to ground.
- One of the headlamp fuses in the underhood fuse block are open.
- The DRL resistor ground circuit is open.
- The DRL resistor is open or shorted.
- The DRL relay is stuck in the OPEN position.

ACTION TAKEN WHEN THE DTC SETS
The BCM turns off the DRL relay control for the remainder of the ignition cycle.

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

DIAGNOSTIC AIDS
- Check both the LH and RH headlamps for proper operation.
- Check both the LT HDLP and RT HDLP fuses.
- If the DTC is a history DTC, the problem may be intermittent.

TEST

Step 1 - Step 14:

Step 15 - Step 20: