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 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
  - Perform the TESTING FOR AN INTERMITTENT CONDITION procedure. Refer to TESTING FOR AN INTERMITTENT CONDITION .
CHECK THE (L3) LICENSE PLATE LAMP CONTROL CIRCUIT FOR A SHORT TO VOLTAGE
1. Turn the Park Lamps off.
2. Turn the ignition off.
3. Disconnect the License Plate Lamp harness connectors.
4. Disconnect the BCM C5/E harness connector.
5. Turn the ignition on.
6. Measure the voltage on the (L3) License Plate Lamp Control circuit at the License Plate Lamp harness connectors.
  Is there any voltage present?
  
  Yes
  - Repair the short to voltage in the (L3) License Plate Lamp Driver circuit.
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
  No
  - Go To 3
CHECK THE (L3) LICENSE PLATE LAMP CONTROL CIRCUIT FOR AN OPEN
1. Turn the ignition off.
2. Measure the resistance of the (L3) License Plate Lamp Control circuit between the License Plate Lamp harness connectors and the BCM C5/E harness connector.
  Is the resistance below 3.0 Ohms?
  
  Yes
  - Go To 4
  No
  - Repair the open in the (L3) License Plate Lamp Control circuit.
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
CHECK THE (Z923) GROUND CIRCUIT FOR AN OPEN
NOTE:
The test light must illuminate brightly. Compare the brightness to that of a direct connection to the battery.
1. Using a 12-volt test light connected to 12-volts, check the (Z923) Ground circuit at the License Plate Lamp harness connectors.
  Does the test light illuminate brightly for both connections?
  
  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 LICENSE PLATE LAMPS
1. Turn the ignition off.
2. Connect the BCM C5/E harness connector.
3. Connect a 12-volt test light between ground and the (L3) License Plate Lamp Control circuit at the License Plate Lamp harness connector.
4. Turn the ignition on.
5. Turn the Park Lamps on.
  Does the test light illuminate brightly for both connections?
  
  Yes
  - Replace the License Plate Lamp Bulb in accordance with the Service Information. Refer to LAMP, LICENSE PLATE, REMOVAL AND INSTALLATION .
  - 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.