Sierra Denali AWD V8-6.0L VIN N (2004)
Steps 1-4
Steps 5-6
The number(s) below refer to the step number(s) on the diagnostic table.
2. Lack of communication may be due to a partial or total malfunction of the class 2 serial data circuit. The specified procedure will determine the
particular condition.
3. The presence of DTCs indicates that the PCM or TAC has detected a fault.
4. 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.
5. This step insures that the PTO options in the scan tool are set according to the upfitters recommendations.
