Test Description
WARNING: This page is about a different car, the 2002 GMC Sierra, 2002 GMC Cab & Chassis Sierra, 2002 Chevrolet Silverado, and 2002 Chevrolet Cab & Chassis Silverado. 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 checks for this condition.
- 4) - This step determines if the fuse blows due to a short to ground on the battery positive voltage circuit.
- 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 DTC 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" indicates 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 affect the setting of DTC C0300. Perform the diagnostics for powertrain DTCs P0502 and P0503 first.
- 10) - Perform diagnostics for DTC C0300 and C0305 first before addressing other DTCs. DTC C0300 and C0305 can be responsible for setting other DTCs.