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 B2585 00: Park Lamp Control CircuitDiagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
Park Lamp Switch ON Signal | 1 | 1 | 1 | -- |
LT/POS/LP Relay Control | 1 | 1 | B2585 00 | -- |
License Lamp Control | 1 | 1 | 1 | -- |
Park Lamp Control | 1 | 1 | 1 | -- |
License Lamp Ground | -- | 1 | -- | -- |
Park Lamps - LF Ground | -- | 1 | -- | -- |
Park Lamps - RF Ground | -- | 1 | -- | -- |
Tail/Stop and Turn Signal Lamps - LR Ground | -- | 1 | -- | -- |
Tail/Stop and Turn Signal Lamps - RR Ground | -- | 1 | -- | -- |
Turn Signal/Multifunction Switch Ground | -- | 1 | -- | -- |
1. Park, License, and/or Tail Lamps Malfunction | ||||
Circuit/System Description
Battery positive voltage is applied at all times to both the coil and switch sides of the LT/POS/LP relay located in the rear fuse block. The turn signal/multifunction switch is suppled with ground at G200 at all times. When the headlamp 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 LT/POS/LP and RT/POS/LP fuses to all of the park, tail, license, and marker lamps.
Conditions for Running the DTC
| • | Battery voltage must be between 9-16 volts. |
| • | Park lamps ON. |
Conditions for Setting the DTC
DTC B2585 00 will set when the BCM detects a short to voltage in the park lamp relay control circuit.
Actions Taken When the DTC Sets
When DTC B2585 00 is present, the park lamps will not operate.
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
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 Testing
- Ignition OFF, disconnect the LT/POS/LP relay.
- Ignition ON, verify a test lamp does not illuminate between the control circuit terminal 87 and ground.
- Verify a test lamp illuminates between the B+ circuit terminal 30 and ground.
- Verify a test lamp illuminates between the B+ circuit terminal 85 and ground.
- Connect a test lamp between the B+ circuit terminal 85 and the control circuit terminal 86.
- Command the Parks Lamps ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.
- If all circuits test normal, test or replace the LT/POS/LP relay.
| ⇒ | If the test lamp illuminates, test the control circuit for a short to voltage. |
| ⇒ | If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the B+ circuit fuse is open, test the control circuit terminal 87 for a short to ground. If the circuit tests normal, test or replace the LT/POS/LP relay. |
| ⇒ | If the test lamp does not illuminate, test the B+ circuit for an open/high resistance. |
| ⇒ | 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. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for BCM replacement, setup, and programming |
