Diagnostic Test

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.
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
  - Perform the TESTING FOR INTERMITTENT CONDITIONS procedure. Refer to TESTING FOR AN INTERMITTENT CONDITION .
CHECK THE (L899) REAR FOG LAMP FEED CIRCUIT FOR A SHORT TO VOLTAGE
NOTE:
Make sure the Rear Fog Lamps are off when performing this step.
1. Turn the Rear Fog Lamps off.
2. Turn the ignition off.
3. Disconnect the Left and Right Rear Fog Lamp harness connectors.
4. Turn the ignition on.
5. Measure the voltage on the (L899) Rear Fog Lamp Feed circuit at the Left and Right Rear Fog Lamp harness connectors.
  Is there any voltage present for any of the connections?
  
  Yes
  - Repair the short to voltage in the (L899) Rear Fog Lamp Feed circuit.
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
  No
  - Go To 3
CHECK THE (Z943) GROUND CIRCUITS FOR AN OPEN
1. Turn the ignition off.
2. Measure the resistance of the (Z943) Ground circuits between ground and the Left and Right Rear Fog Lamp harness connectors.
  Is the resistance above 3.0 Ohms for any of the connections?
  
  Yes
  - Repair the open in the (Z943) Ground circuit.
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
  No
  - Go To 4
CHECK THE BCM FOR CORRECT OPERATION
1. Turn the ignition on.
2. Turn the Rear Fog Lamps on.
3. Connect a 12-volt test light between ground and the (L899) Rear Fog Lamp Feed circuit at the Left and Right Rear Fog Lamp harness connector.
  Does the test light illuminate for both connections?
  
  Yes
  - Replace the appropriate Rear Fog Lamp in accordance with the Service Information. Refer to LAMP, FOG, REMOVAL AND INSTALLATION .
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
  No
  - Go To 5
CHECK THE (L899) REAR FOG LAMP FEED CIRCUIT FOR AN OPEN
1. Turn the ignition off.
2. Disconnect the BCM C6 harness connector.
3. Measure the resistance of the (L899) Rear Fog Lamp Feed circuit between the Left and Right Rear Fog Lamp harness connectors and the BCM C6 harness connector.
  Is the resistance above 3.0 Ohms for any of the connections?
  
  Yes
  - Repair the open in the (L899) Rear Fog Lamp Feed circuit.
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
  No
  - Go To 6
CHECK RELATED 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 AND INSTALLATION .
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
  No
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
  - Test complete.