2010 Cadillac CTS Sedan AWD V6-3.6L Page 509
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 V.
* Park lamps ON.
Conditions for Setting the DTC
The BCM detects a short to voltage in the park lamp relay control circuit.
Actions Taken When the DTC Sets
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
Exterior Lights Schematics (See: Diagrams/Electrical Diagrams/Lighting and Horns/System Diagram/Exterior Lights Schematics)
Connector End View Reference
Component Connector End Views (See: Diagrams/Connector Views)
Description and Operation
Exterior Lighting Systems Description and Operation (See: Lighting and Horns/Description and Operation/Exterior Lighting Systems Description
and Operation)
Electrical Information Reference
* Circuit Testing (See: Testing and Inspection/Component Tests and General Diagnostics/Circuit Testing/Circuit Testing)
* Connector Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/Connector Repairs/Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (See: Testing and Inspection/Component Tests and General Diagnostics/Circuit
Testing/Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/Wiring Repairs/Wiring Repairs)
Scan Tool Reference
Control Module References (See: Testing and Inspection/Programming and Relearning) for scan tool information
Circuit/System Testing
1. Ignition OFF, disconnect the LT/POS/LP relay.
2. Ignition ON, verify a test lamp does not illuminate between the control circuit terminal 87 and ground.
瀚慖f the test lamp illuminates, test the control circuit for a short to voltage.
3. Verify a test lamp illuminates between the B+ circuit terminal 30 and ground.
瀚慖f 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.
4. Verify a test lamp illuminates between the B+ circuit terminal 85 and ground.
瀚慖f the test lamp does not illuminate, test the B+ circuit for an open/high resistance.
5. Connect a test lamp between the B+ circuit terminal 85 and the control circuit terminal 86.
6. 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.
瀚慖f the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the BCM.
瀚慖f 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.
7. If all circuits test normal, replace the LT/POS/LP relay.
