Cummins ISB4.5 CM2150 Fault Code: 4284 PID: SPN: 5793 FMI: 9 Desired Engine Fueling State – Abnormal Update Rate.

Circuit Description
Normally, 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.

Component Location
The SAE J1939 data link wiring and the SAE J1939 devices vary by OEM options.

Conditions for Running the Diagnostics
The first part of the diagnostic runs continuously while the keyswitch is in the ON posistion or the engine is running.

Conditions for Setting the Fault Codes
The ECM did not receive a message from the multiplexed device.

Action Taken When the Fault Code is Active
The ECM illuminates the amber CHECK ENGINE lamp and/or the malfunction indicator lamp (MIL) immediately when the diagnostic runs and fails.

Conditions for Clearing the Fault Code
To validate the repair, 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 ECM will turn off the amber CHECK ENGINE lamp immediately after the diagnostic runs and passes.
-For On-Board Diagnostics (OBD) engines, the ECM will extinguish the Malfunction Indicator Lamp (MIL) after three consecutive trips where 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 on board diagnostic (OBD) applications.

Possible Causes
-Incorrect ECM software for this application.
-A malfunctioning SAE J1939 datalink circuit.