Diagnostic Test
- TEST FOR INTERMITTENT CONDITION
- Turn the ignition on.
- With the scan tool, clear all FCM DTCs.
- Shift the transmission into reverse.
- With the scan tool, read DTCs.
Does the scan tool display: B1668-REVERSE LAMP CONTROL CIRCUIT HIGH?
Yes
- Go to step 2
No
- The conditions that caused this code to set are not present at this time. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors.
- Perform the BODY VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Front Control (FCM) - Standard Procedure .
- (L1) BACK-UP LAMP FEED CIRCUIT SHORT TO VOLTAGE
- Turn the ignition off.
- Disconnect the IPM C2 harness connector.
- Turn the ignition on.
- Measure the voltage on the (L1) Back-up Lamp Feed circuit.
Is the voltage greater than 10.0 volts?
Yes
- Repair the short to voltage in the (L1) Back-up Lamp Feed circuit.
- Perform the BODY VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Front Control (FCM) - Standard Procedure .
No
- Go to step 3
- CHECK (L1) BACK-UP LAMP FEED CIRCUIT IN IPM FOR A SHORT TO BATTERY VOLTAGE
- Turn the ignition off.
- Disconnect the Front Control Module (FCM) from the IPM 49-way connector.
- Reconnect the IPM C2 harness connector.
- Measure the voltage between ground and the (L1) Back-up Lamp circuit.
Is there any voltage present?
Yes
- Replace the Integrated Power Module (IPM) in accordance with the Service Information.
- Perform the BODY VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Front Control (FCM) - Standard Procedure .
No
- Replace the Front Control Module (FCM) in accordance with the Service Information.
- Perform the BODY VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Front Control (FCM) - Standard Procedure .