Diagnostic Test

CHECK FOR AN ACTIVE DTC
1. Turn the ignition on.
2. Apply the Brake Pedal.
3. With the scan tool, read the Body Control Module (BCM) DTCs and record on the repair order.
  Is the DTC active?
  
  Yes
  - Go To 2
  No
  - 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. If no problems are found, test complete.
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
CHECK THE CENTER HIGH MOUNTED STOP LAMP (CHMSL)
1. Turn the ignition off.
2. Disconnect the Center High Mounted Stop Lamp harness connector.
3. Turn the ignition on.
4. Apply the Brake Pedal.
5. With the scan tool, read the BCM DTCs.
  Is the DTC active?
  
  Yes
  - Go To 3
  No
  - Replace the Center High Mounted Stop Lamp Bulb in accordance with the Service Information. Refer to LAMP, CENTER HIGH MOUNTED STOP, REMOVAL .
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
CHECK THE (L51) BRAKE LAMP SWITCH OUTPUT CIRCUIT FOR A SHORT TO GROUND
1. Turn the ignition off.
2. Disconnect the BCM C6/F harness connector.
3. Check for continuity between ground and the (L51) Brake Lamp Switch Output circuit Center High Mounted Stop Lamp harness connector.
  Is there continuity between ground and the (L51) Brake Lamp Switch Output circuit?
  
  Yes
  - Repair the short to ground in the (L51) Brake Lamp Switch Output circuit.
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
  No
  - Replace the Body Control Module (BCM) in accordance with the Service Information. Refer to MODULE, BODY CONTROL (BCM), REMOVAL .
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .