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 right and left 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 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 DRL relay control circuit is open. |
| • | The DRL relay output circuit is open. |
| • | The right headlamp power battery positive voltage circuit is open. |
| • | The left headlamp power battery 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 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 HDLP fuses. |
| • | Diagnose all other DRL DTCs before DTC B2600. |
| • | If the DTC is a history DTC, the problem may be intermittent. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems. |
Test Description
The number below refers to the step number on the diagnostic table.
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 |
Does the DRL relay turn ON and OFF with each command? | Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems | Go to Step 3 | |
3 |
Does the test lamp illuminate? | Go to Step 4 | Go to Step 8 |
4 |
Does the test lamp illuminate? | Go to Step 6 | Go to Step 5 |
5 | Test the control circuit of the DRL relay for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 11 | Go to Step 7 |
6 | Inspect for poor connections at the DRL relay. 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 11 | Go to Step 9 |
7 | Inspect for poor connections at the harness connector of the body control module (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 11 | Go to Step 10 |
8 | Repair an open, high resistance, or short to ground in the ignition positive voltage circuit of the DRL relay. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 11 | -- |
9 | Replace the DRL relay. Refer to Relay Replacement in Wiring Systems. Did you complete the replacement? | Go to Step 11 | -- |
10 | 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 11 | -- |
11 |
Does the DTC reset? | Go to Step 2 | System OK |
