Intermittent Service 4WD Indicator C0305 - keywords lamp light MIL NP8 reluctor ring TCCM tone transfer transfercase wheel

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

Intermittent Service 4WD Indicator with DTC C0305 stored in the Transfer Case Control Module.

Dimensional variances in the front speed sensor stamped steel tone ring may set this code on some vehicles. If the tone ring has been determined to be the cause of the code, the only appropriate repair is to replace the stamped steel tone wheel with the former powdered metal part. This will involve a transfer case teardown on affected vehicles.

Transfer case production with the stamped tone wheel was discontinued on 2/21/06. The stamped steel reluctor was never released into the GMSPO system. The only available part is the former powdered metal piece.

Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.