Diagnostic Instructions
| • | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
| • | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
| • | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
DTC Descriptor
DTC B2600 00: Daytime Running Lamp Control CircuitDiagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
DRL Ambient Light Sensor Signal | B2645 03 | B2645 07 | B2645 07 | -- |
DRL Relay Control | 1 | 1 | B2600 00 | -- |
Left Low Beam Headlamp Control | 2 | 2 | 2 | -- |
Right Low Beam Headlamp Control | 2 | 2 | 2 | -- |
DRL Ambient Light Sensor Low Reference | -- | B2645 07 | -- | -- |
Right Headlamp Low Beam Ground | -- | 2 | -- | -- |
Right Headlamp Low Beam Ground | -- | 2 | -- | -- |
1. Daytime Running Lamps (DRL) Malfunction 2. Headlamps Malfunction - Low Beam | ||||
Circuit Description
Battery positive voltage is applied at all times to both the coil and switched sides of the DRL PCB Relay. 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 PCB relay coil. With the relay energized, voltage is applied through the switch side of the relay, both LOW BEAM Fuses, and the headlamp low beam supply voltage circuits to the low beam headlamps.
Conditions for Running the DTCs
| • | The headlamp switch is in the AUTO position. |
| • | The transmission range selector is not in the PARK position. |
Conditions for Setting the DTC
The BCM detect a short to voltage in the DRL relay control circuit.
Action Taken When the DTC Sets
The BCM will deactivate the DRL relay for the remainder of the ignition cycle.
Conditions for Clearing the DTC
| • | The condition responsible for setting the DTC no longer exists. |
| • | A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred. |
Reference Information
Schematic Reference
Headlights/Daytime Running Lights (DRL) Schematics
Connector End View Reference
Description and Operation
Exterior Lighting Systems Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
Ignition ON, command the DRLs ON with a scan tool. The DRL Relay Command parameter should display On and the DRLs should illuminate.
Circuit/System Testing
- Ignition OFF, disconnect the X4 harness connector at the BCM.
- Ignition ON, verify that a test lamp does not illuminate between the control circuit terminal 23 and B+.
- Install a 10A fused jumper wire between the control circuit terminal 23 and ground. The DRLs should illuminate.
- If all circuits test normal, replace the BCM.
| ⇒ | If the test lamp illuminates, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the underhood fuse block. |
| ⇒ | If the DRLs do not illuminate, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the underhood fuse block. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for BCM replacement, setup, and programming |
