Cummins ISB CM850 (2003-06) Fault Code: 285 PID: SID 231 SPN: 639 FMI: 9 SAE J1939 Multiplexing PGN Timeout Error – Abnormal Update Rate.

Posted by PerDiezel Solutions on January 18, 2026

Cummins ISB CM850 (2003-06) Fault Code: 285 PID: SID 231 SPN: 639 FMI: 9 SAE J1939 Multiplexing PGN Timeout Error – Abnormal Update Rate. The Cummins? ECM did not receive a multiplexed message from an OEM VECU or SIM within the time limit or did not receive it at all.

Verify the electronic control module (ECM) calibration is correct. Check the calibration revision history found on QuickServe? Online for applicable fixes to the calibration stored in the ECM. If necessary, calibrate the ECM. Refer to Procedure 019-032 in Section 19.

When this fault code is active, some multiplexed devices may not function as desired.

This fault can occur for the following reasons:

1)When the ECM is set up properly (components enabled and OEM VECU source addressed correctly) to receive information from an OEM VECU, but the OEM VECU is actually transmitting a message that says that component is not available for multiplexing. This can be caused when a multiplexed component is enabled in the Cummins? ECM, but the OEM VECU source address of the VECU transmitting the component message is incorrect in the Cummins? ECM, or the OEM VECU is not set up to transmit the multiplexed component message.
2)This fault can also be caused by a malfunctioning J1939 data link connection between the OEM VECU and Cummins? ECM, a malfunctioning connection between the component and the OEM VECU, malfunctioning OEM VECU or malfunctioning Cummins? ECM. It may be necessary to contact the OEM for proper multiplexing configuration.

Possible repairs:

1)Repair or replace the OEM harness.

Cummins ISB CM850 (2003-06) Fault Code: 284 PID: SID 221 SPN: 1043 FMI: 4 Engine Speed/Position Sensor (Crankshaft) Supply Voltage Circuit – Voltage Below Normal or Shorted to Low Source. Low voltage detected on the ECM voltage supply line to engine speed sensor.

Cummins ISB CM850 (2003-06) Fault Code: 281 PID: SID 126 SPN: 1347 FMI: 7 Fuel Pump Pressurizing Assembly 1 – Mechanical System Not Responding Properly or Out of Adjustment. A pumping imbalance between the front and rear pumping plungers has been detected.

Cummins ISB CM850 (2003-06) Fault Code: 275 PID: SID 126 SPN: 1347 FMI: 7 Fuel Pumping Element Number 1 (Front) – Mechanical System Not Responding Properly or Out of Adjustment.

Cummins ISB CM850 (2003-06) Fault Code: 272 (ISC – Auto) PID: SID 126 SPN: 1347 FMI: 3 High Fuel Pressure Solenoid Valve Circuit – Voltage Above Normal or Shorted to High Source. High signal voltage or open circuit detected at the fuel pump actuator circuit.

Cummins ISB CM850 (2003-06) Fault Code: 272 (Auto) PID: SID 126 SPN: 1347 FMI: 3 High Fuel Pressure Solenoid Valve Circuit – Voltage Above Normal or Shorted to High Source. Electronic fuel control actuator shorted high.

Cummins ISB CM850 (2003-06) Fault Code: 271 (ISC – Auto) PID: SID 126 SPN: 1347 FMI: 4 High Fuel Pressure Solenoid Valve Circuit – Voltage Below Normal or Shorted to Low Source. Low signal voltage detected at the fuel pump actuator circuit.

WARNING!