| Subject: | NVG246 NP8 4WD Inoperative DTC C0308 ATC Fuse Open |
| Models: | 1999-2000 Cadillac Escalade |
| 1998-1999 Chevrolet Pickup |
| 1999-2002 Chevrolet Silverado |
| 1998-2002 Chevrolet Suburban, Tahoe |
| 1998-1999 GMC Pickup, Suburban |
The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in the PI.
Condition/Concern:
Four wheel drive inoperative and the 4WD service light will illuminate. Diagnosis may reveal that the ATC fuse could be open, possible DTC C0308, or various "U" codes may be set. The encoder motor may also be shorted or the TCCM may be damaged.
Recommendation/Instructions:
Perform a component check to ensure the encoder motor is not damaged. Verify TCCM and encoder motor ground integrity. Refer to the applicable schematics for the TCCM and encoder motor grounds. If the TCCM and Encoder motor ground integrity are good,
check grounds G102 and G107. Refer to the shop manual or eSI for the location of G102 and G107.
The transfer case schematics will not show grounds G102 and G107. These grounds are various engine, chassis and body grounds. If G102 and G107 are loose the TCCM and possibly the encoder motor are being used as a ground path.
Please follow this diagnosis 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.
