ISM Real-Time Clock

Your engine ECM may or may not be configured with a real time clock feature depending on your engine model. Check with your Cummins distributor for specific details for the real time clock feature.

In order to provide comprehensive and useful information pertaining to a wide range of operational events, the Engine Control Module (ECM) records and stores relevant data for future review.

In addition to the recording and storing of information, each operational event is time stamped to enable more detailed and accurate analysis. Two different measures of time are available to the customer, either time using ECM cumulative hours, or date and real time based on units of year, month, day of month, hour (24 hour base), minute and second. Real time values are provided by the Real Time Clock feature.

Operational events that are time stamped include diagnostic Trouble Codes (Fault Codes), Powertrain Torque history, Engine Torque history, Engine Protection Fault history, J1939 Control History, Audit Trail details, Information Log and Engine Data Files.

A battery backup module is available and strongly recommended, to maintain constant power to the Real Time Clock. Should the battery back up module not be installed, a loss of power in excess of 5 seconds will cause a loss of Real Time Clock accuracy and result in the generation of a diagnostic fault code together with the illumination of a fault code warning lamp.

It should be noted that, as the backup module is installed in the engine harness, if the harness is disconnected from the ECM for any reason and in excess of 5 seconds, the Real Time Clock will experience a power loss and the appropriate diagnostic fault code will be generated. Once again, the fault code and warning lamp can only be reset using the relevant service tool.