Diagnostic Aids

WARNING: This page is about a different car, the 2004 Pontiac Sunfire and 2004 Chevrolet Cavalier. However, it is still accessible from the selected car via links, so may be relevant.

When more than one loss of communication DTC is set in either one module or in several modules, diagnose the DTCs in the following order:
- Current DTCs before history DTCs, unless instructed otherwise in the diagnostic table.
- The DTC which is reported the most times.
- From the lowest number DTC to the highest number DTC.
When multiple loss of communication DTCs are set, the cause is likely to be two opens in the class 2 serial data circuit. Use the class 2 serial data circuit schematic in order to determine the location of the opens. Refer to SYSTEM WIRING DIAGRAMS ,