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. With the scan tool, read Body Control Module (BCM) DTCs and record on the repair order.
2. Record the Environmental Data and any DTCs.
3. With the scan tool, erase DTCs.
4. Using the recorded Environmental Data, along with the When Monitored and Set Conditions above, operate the vehicle in the conditions that set the DTC.
5. With the scan tool, read BCM DTCs.
  Did the DTC return?
  
  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 (B122) BRAKE LAMP ACTIVATION RELAY CONTROL CIRCUIT FOR A SHORT TO VOLTAGE
1. Turn the ignition off.
2. Disconnect the Trailer Tow Module harness connector.
3. Turn the ignition on.
4. Measure the voltage on the (B122) Brake Lamp Activation Relay Control circuit at the Trailer Tow Module harness connector.
  Is there any voltage present?
  
  Yes
  - Go To 4
  No
  - Go To 3
CHECK THE BCM BRAKE LAMP ACTIVATION RELAY CONTROL OUTPUT
1. Activate the Stop Lamps.
2. Connect a 12-volt test light, connected to 12-volts, to the (B122) Brake Lamp Activation Relay Control circuit at the Trailer Tow Module harness connector.
  Does the test light illuminate?
  
  Yes
  - Replace the Trailer Tow Module in accordance with the Service Information.
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
  No
  - Go To 5
CHECK THE (B122) BRAKE LAMP ACTIVATION RELAY CONTROL CIRCUIT FOR A SHORT TO ANOTHER CIRCUIT IN THE HARNESS CONNECTOR
1. Turn the ignition off.
2. Disconnect the BCM C6 harness connector.
3. Check for continuity between the (B122) Brake Lamp Activation Relay Control circuit and all other circuits on the BCM C6 harness connector.
  Is there continuity between the (B122) Brake Lamp Activation Relay Control circuit and any other circuit(s)?
  
  Yes
  - Repair the short between the (B122) Brake Lamp Activation Relay Control circuit and the circuit that has continuity.
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
  No
  - Go To 5
CHECK RELATED BCM HARNESS CONNECTIONS
1. Disconnect all BCM harness connectors.
2. Disconnect all related in-line harness connections (if equipped).
3. Disconnect the related component harness connectors.
4. Inspect harness connectors, component connectors, and all male and female terminals for the following conditions:
  - Proper connector installation.
  - Damaged connector locks.
  - Corrosion.
  - Other signs of water intrusion.
  - Weather seal damage (if equipped).
  - Bent terminals.
  - Overheating due to a poor connection (terminal may be discolored due to excessive current draw).
  - Terminals that have been pushed back into the connector cavity.
  - Perform a terminal drag test on each connector terminal to verify proper terminal tension.
  Repair any conditions that are found.
5. Reconnect all BCM harness connectors. Be certain that all harness connectors are fully seated and the connector locks are fully engaged.
6. Reconnect all in-line harness connectors (if equipped). Be certain that all connectors are fully seated and the connector locks are fully engaged.
7. Reconnect all related component harness connectors. Be certain that all connectors are fully seated and the connector locks are fully engaged.
8. With the scan tool, erase DTCs.
9. Using the recorded Environmental Data, along with the When Monitored and Set Conditions above, operate the vehicle in the conditions that set the DTC.
10. With the scan tool, read BCM DTCs.
  Did the DTC return?
  
  Yes
  - 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 .
  No
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
  - Test complete.