B2585
DTC B2585
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 B2585
- Park Lamp Control Circuit
Diagnostic Fault Information
Circuit/System Description
Battery positive voltage is applied at all times to both the coil and switch sides of the PRK/LAMP relay located in the underhood fuse block. The turn signal/multifunction switch is supplied with ground at all times. When the headlamp and panel dimmer switch is placed in either the HEAD or PARK position, ground is applied to the park lamp signal circuit to the body control module (BCM). The BCM responds by applying ground to the park lamp relay control circuit. This energizes the park lamp relay coil causing the relay switch contacts to close allowing battery voltage to flow through the FRT PRK LAMP and REAR PRK LAMP fuses to all of the park, tail, license, and marker lamps.
Conditions for Running the DTC
The battery voltage must be between 9-16 V.
Conditions for Setting the DTC
The park lamp relay control circuit is shorted to voltage.
Action Taken When the DTC Sets
The park lamps will be inoperative from the headlamp and panel dimmer switch.
Conditions for Clearing the DTC
* This DTC will clear on current status after the condition for setting the fault is corrected.
* A history DTC will clear after 100 consecutive ignition cycles without a fault present.
Reference Information
Schematic Reference
Exterior Lights Schematics Exterior Lights Schematics
Connector End View Reference
Component Connector End Views Connector End Views By Name
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 Control Module References for scan tool information
Circuit/System Testing
1. Ignition OFF, disconnect the park lamp relay.
2. Connect a test lamp between the relay coil control circuit terminal 86 and B+.
3. Ignition ON, command the Parking Lamps 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.
4. If all circuits test normal, replace the relay.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic procedure.
* Relay Replacement (Attached to Wire Harness) Relay Replacement (Attached to Wire Harness)Relay Replacement (Within an Electrical Center) Relay Replacement (Within an Electrical Center)
* Control Module References Control Module References for BCM replacement, setup, and programming