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 |
|---|---|---|---|---|
Right Headlamp Low Beam Voltage Supply | 1, 3 | 1, 3 | 3 | -- |
Left Headlamp Low Beam Voltage Supply | 1, 3 | 1, 3 | 3 | -- |
DRL Ambient Light Sensor Signal | B2645 03 | B2645 07 | B2645 07 | -- |
DRL Relay Control | 2 | 1 | B2600 00 | -- |
Ground - DRL Ambient Light Sensor | -- | B2645 07, 1 | -- | -- |
Ground - Left Headlamp Low Beam | -- | 3 | 3 | -- |
Ground - Right Headlamp Low Beam | -- | 3 | 3 | -- |
| ||||
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 park brake is unapplied. |
| • | The engine is running. |
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
Lighting Systems Connector End Views
Electrical Information Reference
Scan Tool Reference
Circuit/System Verification
Carefully supply sufficient light to simulate daylight conditions to the ambient light sensor. With the engine running, headlamp switch in AUTO position, and the park brake released, the day time running lamps should illuminate.
Circuit/System Testing
- Ignition OFF, disconnect the C4 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 day time running lamps should illuminate.
- If all circuits test normal, replace the BCM.
| ⇒ | If the test lamp illuminates, test the control circuit for a short to ground. If the circuit tests normal, replace the underhood fuse block. |
| ⇒ | If the day time running lamps 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 |
