This bulletin applies to 2005-2010 Jeep Grand Cherokee models equipped with a 3.0L V6 engine. A customer may note that the “Service 4WD” indicator in the instrument cluster is illuminated.
They may also note that the transfer case will not shift from 4WD High, 4WD Low, and/or Neutral once the lamp has illuminated. Further investigation may show that DTC C140F is stored or active in the Final Drive Control Modules (FDCM) memory.
1. Using the wiTECH, record the FDCM software number.
2. Was the FDCM software number 56044129AP, 56044199AP or 68235713AB?
- Yes: The FDCM software is at the latest level. Refer to the standard diagnostic information for C140F. Refer to DealerCONNECT>Service>TechCONNECT>Service Info>28 – DTC-based diagnostics>Module, Final Drive Control (FDCM)>Diagnosis and Testing>C140F-TRANSFER CASE RANGE POSITION SENSOR ERRATIC PERFORMANCE for additional information.
- No: Proceed to the next step.
3. Install a battery charger to ensure that battery voltage does not drop below 13.2 volts or above 13.5 volts during the flash process. Reprogram the FDCM with the latest software.
4, Clear any DTCs that may have been set in other modules due to reprogramming.
5. Turn the ignition key to the OFF position and leave off for at least five seconds. Then cycle the key ON for at least five seconds. Perform a total of three key OFF and ON cycles, making sure that there is at least a five-second pause between each key cycle.
6. Using the wiTECH, verify that DTC C140F is not active in the FDCM memory.
7. If the DTC is still active, verify that all harness and connections into the FDCM and into the transfer case actuator are free of bent, loose or corroded terminals.