Rainier AWD L6-4.2L VIN S (2005)
Transfer Case Actuator: All Technical Service Bulletins
Drivetrain - 4X4 Lamp Flashing/4WD Inoperative/DTC's Set
Bulletin No.: 04-04-21-004
Date: December 16, 2004
TECHNICAL
Subject:
4WD Switch Indicator Lights Flashing, 4WD Inoperative, DTCs C0327, P0550 Set (Replace Transfer Case Encoder Sensor, Reprogram TCCM)
Models:
2004-2005 Buick Rainier
2002-2005 Chevrolet TrailBlazer, TrailBlazer EXT
2002-2005 GMC Envoy, Envoy XL
2004-2005 GMC Envoy XUV
2002-2004 Oldsmobile Bravada
with Four-Wheel Drive (4WD)
Condition
Some customers may comment that the Service 4WD light is on, the 4WD system is inoperative or the 4WD switch indicator lights are blinking.
Service Diagnosis
Technicians may find DTC C0327 in the Transfer Case Control Module (TCCM). This would indicate an encoder sensor malfunction.
It is also possible that the module may be in a mode that will not allow any shifts or updates for the software or calibrations. If this occurs, the TREC
fuse (in the engine compartment) must be pulled and reinstalled after 30 seconds.
This should allow further operation and service of the system. If a C0550 code is found, this is an unrelated concern and SI diagnostics should be
followed for this concern.
Correction
Important:
Carefully handle and install the new encoder. Improper installation of the encoder could result in a repeat failure.
1.
Raise the vehicle.
2.
Disconnect the transfer case motor/encoder wiring harness.
3.
Remove the four bolts that secure the motor/encoder to the transfer case.
4.
Remove the motor/encoder from the transfer case.
5.
Remove the black plastic gasket/over plate from the motor/encoder.
