Diagnostic Test

WARNING: This page is about a different car, the 2017 Jeep Cherokee. However, it is still accessible from the selected car via links, so may be relevant.

CHECK FOR AN ACTIVE DTC
1. Turn the ignition on.
2. Apply the Brake Pedal.
3. 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 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 DTCs.
  Does the scan tool display this DTC as 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 (L56) BRAKE LAMP SWITCH OUTPUT CIRCUIT FOR A SHORT TO GROUND
1. Turn the ignition off.
2. Disconnect the BCM C6 harness connector.
3. Measure the resistance between ground and the (L56) Brake Lamp Switch Output circuit.
  Is the resistance above 10K Ohms?
  
  Yes
  - Replace the BCM in accordance with the Service Information. Refer to MODULE, BODY CONTROL (BCM), REMOVAL .
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
  No
  - Repair the short to ground in the (L56) Brake Lamp Switch Output circuit.
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .