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.

VERIFY THE DTC IS ACTIVE
1. Turn the ignition on.
2. With the scan tool, clear all DTCs.
3. Wait 10 seconds.
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 STOP LAMP TRAILER TOW RELAY
1. Turn the ignition off.
2. Remove the Stop Lamp Trailer Tow Relay and substitute it with a known good relay.
3. Turn the ignition on and wait 10 seconds.
4. With the scan tool, read DTCs.
  Is the status Active for this DTC?
  
  Yes
  - Go To 3
  No
  - Replace the Stop Lamp Trailer Tow Relay.
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
CHECK THE (B122) TRAILER TOW STOP LAMP RELAY CONTROL CIRCUIT FOR A SHORT TO GROUND
1. Turn the ignition off.
2. Remove the Stop Lamp Trailer Tow Relay.
3. Disconnect the BCM C6 harness connector.
4. Check for continuity between ground and the (B122) Trailer Tow Stop Lamp Relay Control circuit.
  Is there continuity between ground and the (B122) Trailer Tow Stop Lamp Relay Control circuit?
  
  Yes
  - Repair the short to ground in the (B122) Trailer Tow Stop Lamp Relay Control circuit.
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
  No
  - Go To 4
CHECK THE (B122) TRAILER TOW STOP LAMP RELAY CONTROL CIRCUIT FOR AN OPEN
1. Measure the resistance of the (B122) Trailer Tow Stop Lamp Relay Control circuit between the Stop Lamp Trailer Tow Relay harness connector and the BCM C6 harness connector.
  Is the resistance above 3.0 Ohms?
  
  Yes
  - Repair the open in the (B122) Trailer Tow Stop Lamp Relay Control circuit.
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
  No
  - Go To 5
INSPECT RELATED WIRING AND CHECK FOR TSBS
1. Turn the ignition off.
2. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Stop Lamp Trailer Tow Relay and the BCM.
3. Look for any chafed, pierced, pinched, or partially broken wires.
4. Look for broken, bent, pushed out or corroded terminals.
5. Perform any Technical Service Bulletins that may apply.
  Were any problems found?
  
  Yes
  - Repair as necessary.
  - 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 .