Circuit DescriptionThe Engine Control Module (ECM) calculates a calibration memory checksum based on the values of certain parameters in the ECM. This checksum is compared to an expected value in the ECM to detect tampering.

Component LocationThe ECM mounting location varies, depending on the engine model, and may be mounted either on or off the engine.

Conditions for Running the DiagnosticsThis diagnostic runs continuously when the keyswitch is in the ON position or when the engine is running.

Conditions for Setting the Fault CodesThe Engine Control Module (ECM) detected the calibration memory checksum did not match the expected value or it did not complete before ECM shutdown.

Action Taken When the Fault Code is ActiveThe ECM illuminates the amber CHECK ENGINE lamp immediately when the diagnostic runs and fails.Conditions for Clearing the Fault CodeIn order for this fault code to go inactive, a calibration download is necessary.

The fault code status displayed by INSITE™ electronic service tool will change to INACTIVE immediately after the diagnostic runs and passes.The ECM will turn off the amber CHECK ENGINE lamp immediately after the diagnostic runs and passes.

Shop TalkPossible causes of this fault code include:

Malfunctioning ECM software

Tampering of the ECM software

Possible Cause:1) N/A