Test Description
WARNING: This page is about a different car, the 2003 GMC Yukon XL, 2003 GMC Yukon, 2003 Chevrolet Tahoe, 2003 Chevrolet Suburban, and 2003 Cadillac Escalade ESV. However, it is still accessible from the selected car via links, so may be relevant.
The numbers below refer to the step numbers on the diagnostic table.
- 2. Lack of communication may be due to a partial malfunction of the Class 2 serial data circuit or due to a total malfunction of the Class 2 serial data circuit. The specified procedure will determine the particular condition.
- 3. A fuse failure will cause no communication this step has you check for this condition.
- 4. This step determines if the fuse blows when the ignition is turned on.
- 5. This step determines if there is a short to ground in the battery positive circuit causing the fuse to blow.
- 6. This step refers to the table for C0306 for further diagnosis if a transfer case mode change is causing the fuse to blow.
- 7. The presence of DTCs indicates that the transfer case shift control module has detected a fault. Go to symptoms for other concerns.
- 8. The presence of DTCs which begin with "U" indicate some other module is not communicating. The specified procedure will compile all the available information before tests are performed.
- 9. Vehicle speed is provided to the transfer case shift control module via Class 2 and can effect the setting of DTC C0300. Perform the diagnostics for powertrain DTCs P0502 and P0503 first.