B2605
DTC 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 Descriptor
DTC B2605 00
-
Daytime Running Lamp Control 2 Circuit
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. The body control module (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 (ALC) when the headlamp switch is in the AUTO position. In daylight conditions, the BCM will command the DRLs ON by applying ground to the DRL 2 relay via the DRL 2 relay control circuit. When the BCM applies ground to the DRL 2 relay control circuit, the DRL 2 relay coil energizes causing the relay switch contacts to close. With the DRL 2 relay switch contacts closed, battery voltage flows through the DRL 2 fuse to the left and right DRL lamps. 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
The BCM detects a short to voltage in the DRL 2 relay control circuit.
Action Taken When the DTC Sets
The BCM will disable the DRL 2 relay 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/Daytime Running Lights (DRL) Schematics Headlights/Daytime Running Lights (DRL) Schematics
Connector End View Reference
Component Connector End Views A/C Compressor Clutch
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 Verification
1. Ignition ON, verify with a scan tool the park brake switch parameter displays RELEASED.
• If not the specified value, refer to Symptoms - Park Brake Symptoms - Park Brake.
2. Command the DRLs ON and OFF with a scan tool. The daytime running lights should turn ON and OFF when changing between the commanded states.
• If the daytime running lights do not turn ON and OFF when changing between the commanded states, refer to Circuit/System Testing.
Circuit/System Testing
1. Ignition OFF, disconnect the DRL 2 relay.
2. Ignition ON, verify that a test lamp does not illuminate between the control circuit terminal 87 and ground.
• If the test lamp illuminates, test the control circuit for a short to voltage.
3. Verify that a test lamp illuminates between the B+ circuit terminal 86 and ground.
• If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
4. Verify that a test lamp illuminates between the B+ circuit terminal 30 and ground.
• If the test lamp does not illuminate, test the B+ circuit for an open/high resistance.
5. Disconnect the harness connector at the appropriate daytime running lamp.
6. Test for less than 5 ohms between the ground circuit terminal listed below and ground:
* RPO WDA - Terminal 1
* RPO W49/Z88 - Terminal 3
• If greater than the specified range, test the ground circuit for an open/high resistance.
7. Connect the harness connector at the daytime running lamp.
8. Connect a 10 A fused jumper wire between the B+ circuit terminal 30 and the control circuit terminal 87. Verify the daytime running lamp is activated.
• If the daytime running lamp does not activate and the circuit fuse is good, test the control circuit for an open/high resistance. If the circuit tests normal, test or replace the daytime running lamp.
• If the daytime running lamp does not activate, and the circuit fuse is open, test the control circuit for a short to ground. If the circuit tests normal, test or replace the daytime running lamp.
9. Connect a test lamp between the B+ circuit terminal 86 and the control circuit terminal 85.
10. Command the DRL 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 ground. If the circuit tests normal, replace the BCM.
• If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.
11. If all circuits test normal, test or replace the DRL 2 relay.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic procedure.
* Relay Replacement (Within an Electrical Center) Relay Replacement (Within an Electrical Center)Relay Replacement (Attached to Wire Harness) Relay Replacement (Attached to Wire Harness)
* Daytime Running Lamp Replacement Daytime Running Lamp Replacement
* Daytime Running Lamp Bulb Replacement (Enclave) Daytime Running Lamp Bulb Replacement
* Control Module References Programming and Relearning for BCM replacement, programming and setup