C0398

DTC C0398

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Initial Inspection and Diagnostic Overview
* Review Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptor
DTC C0398 5A
- Incremental Sensor - Rotational Position Sensor Correlation Plausibility Failure

Diagnostic Fault Information





Circuit/System Description

The transfer case incremental position sensor and the rotational position sensor are both input to the transfer case control module as to the range or mode the transfer case is in. Both sensors are capable of showing position by degrees. If the two sensors disagree by 5 percent or more this DTC will set.

Conditions for Running the DTC

* The ignition is ON.
* System voltage is 10.5-18 volts.

Conditions for Setting the DTC

Both sensors must be showing a valid position at the time the DTC is set.

Action Taken When the DTC Sets

* Shifting is still disabled until the DTC has cleared itself.
* The SERVICE 4WD indicator remains illuminated for the remainder of the current ignition cycle.

Conditions for Clearing the DTC

* The transfer case shift control module clears the DTC if the condition for setting the DTC is not currently present.
* A history DTC clears after 40 consecutive warm up cycles without a fault present.
* History DTCs can be cleared using a scan tool.

Diagnostic Aids

Each of the two sensors show the transfer case movement in degrees. Find the sensor either the incremental sensor or the RPS that seems to not be showing a reading in degrees and is doing so erratically this is probably the sensor causing the DTC.

Circuit/System Testing

Inspect the RPS sensor for damage at the mating surface with the rotational position shaft.

1. If the RPS sensor shows damage at the mating surface then replace the RPS sensor. If no damage is found attempt to turn the shaft while the transfer case in stationary in one mode.
2. If the shaft can be turned then internal damage has occurred to this shaft, refer to transfer case disassemble and inspection and repair as necessary. If no damage is found and the RPS sensor seems to show a steady degrees rotation reading on the scan tool data list then replace the transfer case two/four wheel drive actuator.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure. Verification Tests

* Transfer Case Disassemble
* Transfer Case Two/Four Wheel Drive Actuator Replacement
* Transfer Case Two/Four Wheel Drive Actuator Position Sensor Replacement