P0603

CIRCUIT DESCRIPTION
The Engine Control Module (ECM) contains data that is essential to running the engine. The ECM continuously checks the integrity of this data.

CONDITIONS FOR RUNNING THE DTC
During the engine power down phase

CONDITIONS FOR SETTING THE DTC
The ECM determines that an internal data test did not pass.

ACTION TAKEN WHEN THE DTC SETS
^ The ECM illuminates the Malfunction Indicator Lamp (MIL) on the first drive trip that the diagnostic runs and fails.
^ The ECM attempts to record the operating conditions in the Freeze Frame, however, since this Diagnostic Trouble Code (DTC) indicates that an internal ECM test did not pass, this information may not be useful for this specific DTC.

Diagnostic Chart:

CONDITIONS FOR CLEARING THE MIL/DTC
^ The ECM turns OFF the MIL after three consecutive drive trips that the diagnostic runs and passes.
^ A History DTC clears after forty consecutive warm-up cycles in which no failures are reported by this diagnostic or any other emission related diagnostic.
^ The scan tool clears the MIL/DTC.

DIAGNOSTIC AIDS
This DTC may set if the battery is disconnected while the ECM is powered-up. This DTC and several others may set if the Switched B+ or the battery supply is removed from the ECM while the ECM is powered up. Test for intermittent or poor connections on the switched B+ and the battery supply circuits at the ECM. Also test the control circuit for the engine controls power relay for in intermittent open or high resistance and inspect the terminal contact at the relay. Refer to Testing for Intermittent and Poor Connections in Diagrams.