Test Description

The numbers below refer to the step numbers on the diagnostic procedure.

• Lack of communication may be because of 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.
• The symptom list in Symptoms will determine the correct diagnostic procedure to use. See SYMPTOM INDEX  table.
• The presence of DTCs which begin with "U" indicate some other module is not communicating. The specified procedure will collect all the available information before you perform tests.