Circuit DescriptionNormally, switches, accelerators, and other components are connected to the engine control module (ECM) directly through individual wires. Multiplexing allows those same components to be hard wired to an original equipment manufacturer (OEM) vehicle electronic control unit (VECU) or transmission electronic control unit (ECU) in the cab. Then component values and states from components such as sensors, accelerators, and switches can be transmitted from the OEM VECU to the Cummins® ECM over the SAE J1939 data link.

Messages sent from OEM VECUs or transmission ECUs are received by the Cummins® ECM and used for controlling the engine. The Cummins® ECM and OEM VECU(s) must be configured properly, so that proper operation of the multiplexed components will occur.

Component LocationThe Engine Control Module (ECM) is mounted on the intake manifold side of the engine.

The Transmission Control Module (TCM) location varies by application, Refer to the OEM service manual for component location.

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 ECM Calibration and the Transmission are mismatched. A SmartAdvantage transmission is installed but the ECM calibration does not support that transmission.

Action Taken When the Fault Code is ActiveThe ECM logs the fault code immediately when the diagnostic runs and fails.Conditions for Clearing the Fault CodeTo validate the repair, perform a key cycle, start the engine and let it idle for 1 minute.The fault code status displayed by INSITE™ electronic service tool will change to INACTIVE immediately after the diagnostic runs and passes.The Reset All Faults command in INSITE™ electronic service tool can be used to clear active and inactive faults, as well as extinguish the MIL for OBD applications.

Shop TalkPossible causes for this fault code include:

ECM Calibration is not correct for the transmission.

Possible Cause:1) ECM calibration