Test Description
WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2003 GMC Yukon XL, 2003 GMC Yukon, 2003 Chevrolet Tahoe, 2003 Chevrolet Suburban, and 2003 Chevrolet Avalanche. 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.
- This step inspects for lack of communication that 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 determines the particular condition.
- The presence of DTCs indicates that the transfer case shift control module has detected a fault. Go to symptoms for other concerns.
- The presence of DTCs which begin with "U" indicate some other module is not communicating. The specified procedure compiles all the available information before tests are performed.
- 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 DTC P0502 and DTC P0503 first.
- Perform diagnostics for DTC C0300 and DTC C0305 first before addressing other DTCs. DTC C0300 and DTC C0305 can be responsible for setting other DTCs.