Diagnostic Procedure
- If multiple class 2 codes are set as current (i.e., U1300, U1301, U1088 or U1153), check for an intermittent short to ground or battery in Purple wire between individual control modules.
- If DTC is current, attempt to establish communications with PCM using scan tool. If communication cannot be established, diagnose PCM. See TESTS W/CODES article in ENGINE PERFORMANCE section. If communication can be established, replace IPC.
- If DTC is history, check for intermittent open in Purple wire between individual control modules.