Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Diagnostic Test
- CHECK FOR AN ACTIVE DTC
- With the scan tool, read Body Control Module (BCM) DTCs and record on the repair order.
- Record the Environmental Data.
- With the scan tool, erase DTCs.
- With the Park Brake firmly applied, shift the gear selector into REVERSE.
- 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 (L16) BACKUP LAMP FEED CIRCUIT FOR A SHORT TO VOLTAGE NOTE:
Make sure the Park Lamps are off when performing this step.
- Shift the gear selector into PARK.
- Turn the ignition off.
- Disconnect the Left Backup Lamp harness connector.
- Disconnect the Right Backup Lamp harness connector.
- Disconnect the Inside Rearview Mirror harness connector.
- Turn the ignition on.
- Measure the voltage on the (L16) Backup Lamp Feed circuit at the Left Backup Lamp harness connector.
Is there any voltage present?
Yes
- Repair the short to voltage in the (L16) Backup Lamp Feed circuit.
- Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
No
- Go To 3
- CHECK THE GROUND CIRCUITS FOR AN OPEN
- Turn the ignition off.
- Measure the resistance between ground and the Ground circuit at the Left Backup Lamp harness connector.
- Measure the resistance between ground and the Ground circuit at the Right Backup Lamp harness connector.
Is the resistance above 3.0 Ohms for any of the connections?
Yes
- Repair the open in the Ground circuit.
- Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
No
- Go To 4
- CHECK THE BCM FOR PROPER OPERATION
- Turn the ignition on.
- With the Park Brake firmly applied, shift the gear selector into REVERSE.NOTE:
The test light must illuminate brightly. Compare the brightness to that of a direct connection to the battery.
- Connect a 12-volt test light between ground and the (L16) Backup Lamp Feed circuit at the Left Backup Lamp harness connector.
- Connect a 12-volt test light between ground and the (L16) Backup Lamp Feed circuit at the Right Backup Lamp harness connector.
- Connect a 12-volt test light between ground and the (L16) Backup Lamp Feed circuit at the Inside Rearview Mirror harness connector.
Does the test light illuminate brightly for all of the connections?
Yes
- Replace the Left or Right Backup Lamp in accordance with the Service Information. If the DTC is still Active after replacing the Backup Lamps, replace the Inside Rearview Mirror in accordance with the Service Information.
- Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
No
- Go To 5
- CHECK THE BACKUP LAMP FEED CIRCUITS FOR AN OPEN
- Shift the gear selector into PARK.
- Turn the ignition off.
- Disconnect the BCM C6/F harness connector.
- Measure the resistance of the (L16) Backup Lamp Feed circuit between the Left Backup Lamp harness connector and the BCM C6/F harness connector.
- Measure the resistance of the (L16) Right Backup Lamp Feed circuit between the Right Backup Lamp harness connector and the BCM C6/F harness connector.
- Measure the resistance of the (L16) Right Backup Lamp Feed circuit between the Inside Rearview Mirror harness connector and the BCM C6/F harness connector.
Is the resistance above 3.0 Ohms for any of the connections?
Yes
- Repair the open in the (L16) Backup Lamp Feed circuit.
- Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
No
- Go To 6
- CHECK RELATED HARNESS CONNECTIONS
- Disconnect all BCM harness connectors.
- Disconnect all related in-line harness connections (if equipped).
- Disconnect the related component harness connectors.
- 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.
- Reconnect all BCM harness connectors. Be certain that all harness connectors are fully seated and the connector locks are fully engaged.
- Reconnect all in-line harness connectors (if equipped). Be certain that all connectors are fully seated and the connector locks are fully engaged.
- Reconnect all related component harness connectors. Be certain that all connectors are fully seated and the connector locks are fully engaged.
- With the scan tool, erase DTCs.
- Using the recorded Environmental Data, along with the When Monitored and Set Conditions above, operate the vehicle in the conditions that set the DTC.
- 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.
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.