Diagnostic Test

WARNING: This page is about a different car, the 2005 Jeep Grand Cherokee. However, it is still accessible from the selected car via links, so may be relevant.

1) TEST FOR INTERMITTENT CONDITION
Turn the ignition on.

Clear all FCM DTC's

Shift the transmission into reverse.

With the scan tool, read DTC's.

Does the scan tool read: B1668-REVERSE LAMP CONTROL CIRCUIT HIGH?

Yes
1. Go To step 2).
No
1. 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.
2. Perform BODY VERIFICATION TEST - VER 1 .
2) (L1) BACK-UP LAMP FEED CIRCUIT SHORT TO VOLTAGE

Fig 1: Checking (L1) Back-Up Lamp Feed Circuit For Short To Voltage
Courtesy of DAIMLERCHRYSLER CORP.

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
1. Repair the (L1) Back-up Lamp Feed circuit for a short to voltage.
2. Perform BODY VERIFICATION TEST - VER 1 .
No
1. Replace the IPM in accordance with the service information.
2. Perform BODY VERIFICATION TEST - VER 1 .