Diagnostic Test

WARNING: This page is about a different variant/trim than selected.

CHECK FOR AN INTERMITTENT CONDITION
1. Turn the ignition on.
2. With the scan tool, clear all DTCs.
3. Activate the Stop Lamps on and off.
4. With the scan tool, read DTCs.
  Does the scan tool display this DTC as active?
  
  Yes
  - Go To 2
  No
  - Test complete. The condition or conditions that originally set this DTC are not present at this time. Using the wiring diagrams as a guide, check all related splices and connectors for signs of water intrusion, corrosion, pushed out or bent terminals and correct pin tension.
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
CHECK THE (L56) BRAKE LAMP SWITCH OUTPUT CIRCUIT FOR A SHORT TO VOLTAGE
1. Turn the ignition off.
2. Disconnect the Center High Mounted Stop Lamp (CHMSL) harness connector.
3. Disconnect the BCM C3 harness connector.
4. Turn the ignition on.
5. Measure the voltage between ground and the (L56) Brake Lamp Switch Output circuit.
  Is there any voltage present?
  
  Yes
  - Repair the short to voltage in the (L56) Brake Lamp Switch Output circuit.
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
  No
  - Go To 3
CHECK THE BCM FOR CORRECT OPERATION
1. Turn the ignition off.
2. Connect the BCM C3 harness connector.
3. Connect a 12-volt test light between the (L56) Brake Lamp Switch Output circuit and ground circuit at the CHMSL harness connector.
4. Turn the ignition on.
5. Activate the Stop Lamps on and off.
  Does the test light illuminate on and off as the Stop Lamps are activated on and off?
  
  Yes
  - Test complete. The condition or conditions that originally set this DTC are not present at this time. Using the wiring diagrams as a guide, check all related splices and connectors for signs of water intrusion, corrosion, pushed out or bent terminals and correct pin tension.
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
  No
  - Replace the BCM in accordance with the Service Information. Refer to MODULE, BODY CONTROL, REMOVAL .
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .