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 the RH and LH headlamps in series with each other with the DRL relay providing the ground path 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.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC B2600 Daytime Running Lamp Control System Circuit
Conditions for Running the DTCs
| • | The ignition switch is in the ON position. |
| • | 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 are present:
| • | The headlamp high beam signal circuit is open. |
| • | The headlamp low beam signal circuit is open. |
| • | The right headlamp battery positive voltage circuit is open. |
| • | The left headlamp battery positive voltage 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 indicator lights. |
Conditions for Clearing the DTC
| • | The conditions for setting the DTC are no longer present. |
| • | A history DTC clears after 100 malfunction free ignition cycles. |
| • | The BCM receives the clear code command from the scan tool. |
Diagnostic Aids
| • | Check both the LH and RH headlamps for proper operation. |
| • | Check both the LH and RH HEADLAMP fuses. |
| • | If the DTC is a history DTC, the problem may be intermittent. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems. |
Step | Action | Yes | No |
|---|---|---|---|
Schematic Reference: Headlights/Daytime Running Lights (DRL) Schematics Connector End View Reference: Master Electrical Component List in Wiring Systems | |||
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information |
2 |
Do the headlamps operate properly? | Go to Step 4 | Go to Step 3 |
3 | Are both the high beam and low beam headlamps on one side inoperative? | Go to Step 6 | Go to Step 7 |
4 | Test the headlamp high beam signal circuit and the headlamp low beam signal circuit for an open or high resistance between the body control module (BCM) and the underhood junction block. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 9 | Go to Step 5 |
5 | Inspect for poor connections at the harness connector of the BCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 9 | Go to Step 8 |
6 | Repair an open, high resistance, or short to ground in the supply voltage circuit of the inoperative headlamp. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 9 | -- |
7 | Repair an open or high resistance in the headlamp high beam signal circuit or the headlamp low beam signal circuit of the inoperative headlamp. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 9 | -- |
8 | Replace the BCM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. Did you complete the replacement? | Go to Step 9 | -- |
9 |
Does the DTC reset? | Go to Step 2 | System OK |
