The BCM detects a short to ground in the CHMSL supply voltage circuit when the stop lamps are commanded ON.
Action Taken When the DTC Sets
The CHMSL will not illuminate.
Conditions for Clearing the DTC
* The conditions for setting the DTC are no longer present.
* A history DTC clears after 100 malfunction-free ignition cycles.
* The BCM receives the clear code command from the scan tool.
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/General Electrical Diagnostic Procedures/Circuit
Testing/Circuit Testing)
* Connector Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic
Procedures/Connector Repairs/Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (See: Testing and Inspection/Component Tests and General Diagnostics/General
Electrical Diagnostic Procedures/Circuit Testing/Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic Procedures/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 harness connector at the center high mounted stop lamp.
2. Test for less than 5.0 ohm between the ground circuit terminal B and ground.
锟斤拷 If greater than the specified range, test the ground circuit for an open/high resistance.
3. Connect a test lamp between the stop lamp control circuit terminal A and ground circuit terminal B.
4. Ignition ON, press and release the brake pedal. The test lamp should turn ON and OFF when changing between the commanded states.
锟斤拷 If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the BCM.
锟斤拷 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 BCM.
5. If all circuits test normal, test or replace the center high mounted stop lamp.
Repair Instructions
Perform the Diagnostic Repair Verification (See: Verification Tests) after completing the diagnostic procedure.
* High Mount Stop Lamp Replacement (Yukon Two-mode Hybrid) (See: Lighting and Horns/Center Mounted Brake Lamp/Service and
Repair/High Mount Stop Lamp Replacement (Yukon Two-mode Hybrid))High Mount Stop Lamp Replacement (Yukon) (See: Lighting and
Horns/Center Mounted Brake Lamp/Service and Repair/High Mount Stop Lamp Replacement (Yukon))High Mount Stop Lamp Replacement
(Avalanche) (See: Lighting and Horns/Center Mounted Brake Lamp/Service and Repair/High Mount Stop Lamp Replacement (Avalanche)
)High Mount Stop Lamp Replacement (Escalade) (See: Lighting and Horns/Center Mounted Brake Lamp/Service and Repair/High Mount
Stop Lamp Replacement (Escalade))
* Control Module References (See: Testing and Inspection/Programming and Relearning) for BCM replacement, setup, and programming
