Diagnostic System Check

TEST DESCRIPTION

Steps 1-7:

The number(s) below refer to the step number(s) 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. The symptoms list in Symptoms will determine the correct diagnostic procedure to use.
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. The presence of DTC P0601, P0602, P0603, P0604 or P0606 indicates an internal fault in the ECM.
6. The presence of DTC B1552, B1656, B1558 or B1973 indicates an internal module fault.
7. The Presence of DTC B1982 or B1983 indicates a low or high voltage condition.