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 (L56) CHMSL DRIVER CIRCUIT FOR A SHORT TO VOLTAGE IN THE HARNESS
1. Turn the ignition off.
2. Disconnect the Center High Mounted Stop Lamp harness connector.
3. Disconnect the BCM C6 harness connector.
4. Turn the ignition on.
5. Measure the voltage between ground and the (L56) CHMSL Driver circuit.
  Is there any voltage present?
  
  Yes
  - Repair the short to voltage in the (L56) CHMSL Driver circuit.
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
  No
  - Go To 3
CHECK THE (L56) CHMSL DRIVER CIRCUIT FOR AN OPEN IN THE HARNESS
1. Turn the ignition off.
2. Measure the resistance of the (L56) CHMSL Driver circuit between the Center High Mounted Stop Lamp harness connector and the BCM C6 harness connector.
  Is the resistance below 5.0 Ohms?
  
  Yes
  - Go To 4
  No
  - Repair the open in the (L56) CHMSL Driver circuit.
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
CHECK THE (Z923) GROUND CIRCUIT FOR AN OPEN IN THE HARNESS
1. Using a 12-volt test light connected to 12-volts, check the (Z923) Ground circuit.
  Does the test light illuminate brightly?
  
  Yes
  - Go To 5
  No
  - Repair the open in the (Z923) Ground circuit.
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
CHECK THE BCM FOR CORRECT OPERATION
1. Turn the ignition off.
2. Reconnect the BCM C6 harness connector.
3. Connect a 12-volt test light between the (L56) CHMSL Driver circuit and the (Z923) Ground circuit at the Center High Mounted Stop Lamp harness connector.
4. Turn the ignition on.
5. Apply the Brake Pedal.
  Does the test light illuminate brightly?
  
  Yes
  - Replace the Center High Mounted Stop Lamp in accordance with the Service Information. Refer to LAMP, CENTER HIGH MOUNTED STOP, REMOVAL .
  - 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 (BCM), REMOVAL .
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .