B2600
DTC B2600 or B2605
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (Diagnostic System Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Strategy Based Diagnosis) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Diagnostic Procedure Instructions) provides an overview of each diagnostic category.
DTC Descriptors
DTC B2600 01
- Left Daytime Running Lamps Control Circuit short to Battery
DTC B2600 02
- Left Daytime Running Lamps Control Circuit Short to Ground
DTC B2600 04
- Left Daytime Running Lamps Control Circuit Open
DTC B2605 01
- Right Daytime Running Lamps Control Circuit short to Battery
DTC B2605 02
- Right Daytime Running Lamps Control Circuit Short to Ground
DTC B2605 04
- Right Daytime Running Lamps Control Circuit Open
Diagnostic Fault Information
Circuit/System Description
The ambient light sensor is used to monitor outside lighting conditions. The ambient light sensor provides a voltage signal that will vary between 0.2 and 4.9 V depending on outside lighting conditions. The body control module (BCM) provides a 5 V reference signal to the ambient light sensor which is permanently grounded. The BCM monitors the ambient light sensor signal circuit to determine if outside lighting conditions are correct for either daytime running lights (DRL) or automatic lamp control when the headlamp switch is in the AUTO position. In daylight conditions, the BCM will command the DRLs ON by applying a pulse width modulated (PWM) voltage to the left and right DRL control circuits illuminating the DRLs. Any function or condition that turns on the headlamps will cancel DRL operation.
Conditions for Running the DTC
* Battery voltage must be between 9-16 V.
* Headlamp switch in AUTO position.
Conditions for Setting the DTC
B2600 01
The BCM detects a short to voltage in the left DRL control circuit.
B2600 02
The BCM detects a short to ground in the left DRL control circuit.
B2600 04
The BCM detects an open in the left DRL control circuit.
B2605 01
The BCM detects a short to voltage in the left DRL control circuit.
B2605 02
The BCM detects a short to ground in the left DRL control circuit.
B2605 04
The BCM detects an open in the left DRL control circuit.
Actions Taken When the DTC Sets
The BCM will disable the appropriate DRL control circuit.
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 Schematics (Headlights Schematics)
Connector End View Reference
Component Connector End Views (Connector Views)
Description and Operation
Exterior Lighting Systems Description and Operation (Exterior Lighting Systems)
Electrical Information Reference
* Circuit Testing (Circuit Testing)
* Connector Repairs (Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (Wiring Repairs)
Scan Tool Reference
Control Module References (Programming and Relearning) for scan tool information
Circuit/System Testing
1. Ignition OFF, disconnect the harness connector at the appropriate E4 daytime running lamp.
2. Ignition OFF, exterior lamps OFF, test for less than 5.0 ohm between the ground circuit terminal 2 and ground.
• If greater than the specified range, test the ground circuit for an open/high resistance.
3. Connect a test lamp between the control circuit terminal 1 and ground.
4. Command the Dedicated Daytime Running Lamp Command ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.
• If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the K9 BCM.
• If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K9 BCM.
5. If all circuits test normal, replace the E4 daytime running lamp.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
* Daytime Running Lamp Bulb Replacement (Daytime Running Lamp Bulb Replacement)
* Daytime Running Lamp Replacement (Daytime Running Lamp Replacement)
* Control Module References (Programming and Relearning) for BCM replacement, setup, and programming