600-902: DIAGNOSTIC TROUBLE CODES: TRANSFER CASE MOTOR
ATTENTION
Refer to the appropriate shop manual for your vehicle to obtain specific service procedures for this part. If you do not have a service manual or lack the skill to install this part, it is recommended that you seek the services of a qualified technician. Pay special attention to all cautions and warnings included in the shop manual. Read and follow all instructions carefully.
Compatible Vehicles
2000–96 K2500 Pickup, 1999–96 K1500 Pickup/Suburban/Tahoe, 1999 Escalade, 2002–01 Durango/Dakota, 1999–96 Yukon
DTC-002: Motor A or Motor B Failure
Description
The transfer case encoder motor houses four (4) separate positions. These positions are used to communicate with the transfer case control module (TCCM), indicating the current mode (2HI, 4HI, 4LO, N) or if the transfer case is between gears. While the transfer case motor is shifting, the TCCM monitors its circuit for proper operation. Simultaneously, the encoder motor monitors its own position. If the encoder motor detects a skipped position or deviates from the specified sequence, it will set a hard encoder fault code and default to a 2HI, 4HI, 2LO, 4LO shift pattern. For the TCCM to set a hard diagnostic trouble code (DTC) like DTC-002, the encoder motor must fail twenty-five percent (25%) of the time.
How to Access the Diagnostic Trouble Code (DTC)
The DTCs are displayed on the transfer case shift control switch. Follow the procedure below to acquire the DTCs:
- Turn the ignition off for ten (10) seconds.
- Using an alligator clip or probe, connect to PIN 13 on the data link connector (DLC) and connect to a ground source. NOTE: The data link connector (DLC) is located under the driver side portion of the instrument panel.
Data Link Connector (DLC) Image Description
A close-up view of a vehicle's data link connector (DLC) with multiple pins. A prominent circular label with the number "13" is positioned over one of the pins, indicating its significance for diagnostic procedures.
- Turn the ignition to the "ON" position. DO NOT START THE VEHICLE!
- Count the number of flashes from the transfer case shift control switch. NOTE: On most vehicles, there will be an initial flash to signify the start of the test, followed by a brief pause. After this initial pause, count the subsequent flashes. Once the flashes have stopped, there will be another brief pause, concluding the diagnostic procedure.
Diagnostic Trouble Code (DTC) Description
DTC-002 is an encoder circuit malfunction.
When to Clear a DTC
The diagnostic trouble code (DTC) should only be erased once the encoder motor has been replaced or repaired.
How to Clear a DTC
The DTC will clear after disconnecting the positive side of the battery for thirty (30) seconds and after the encoder motor concern has been repaired.
Disclaimer
Even though every attempt is made to ensure this information is complete and accurate, it is impossible to account for all possible circumstances or situations. Please consult with a qualified auto technician before attempting to perform any work you are not qualified to do. Automobiles can be hazardous to work on; be sure to take all necessary safety precautions. Failure to do so may result in property damage or personal injury. Certain motor vehicle standards and performance requirements may apply to your motor vehicle (such as Federal Motor Vehicle Safety Standards by the National Highway Traffic Safety Administration). Be sure that your work is performed in accordance with such standards and that you do not disable any motor vehicle safety feature.
