Cummins ISB CM550 (1990-94) Fault Code: 444 PID: SID 232 SPN: 620 FMI: 1 Remote Accelerator Supply Circuit

Posted by PerDiezel Solutions on January 16, 2026

Circuit Description
The remote accelerator supply circuit supplies +5 VDC for the remote accelerator and the
coolant level sensor. These circuits are connected inside the ECM. Faults on these circuits
could also affect the operation of the WIF sensor. These are all OEM options and often do not
apply to your specific vehicle.

NOTE: The connector pin letters shown for the accelerator pedal wiring in these
troubleshooting steps are examples of representative sensors. The connector pin assignments
can vary with equipment manufacturer, but the base troubleshooting logic will still apply.

Component Location
The remote accelerator position sensor is located on the remote accelerator control assembly
somewhere outside the cab. The coolant level sensor will be located in the top of the radiator
or coolant tank. The WIF sensor is located in the fuel filter or fuel filter head.

Cummins ISB CM550 (1990-94) Fault Code: 444 PID: SID 232 SPN: 620 FMI: 3 Remote Accelerator Supply Circuit

Cummins ISB CM550 (1990-94) Fault Code: 443 PID: SID 232 SPN: 620 FMI: 1 Accelerator Position Sensor Circuit

Cummins ISB CM550 (1990-94) Fault Code: 443 PID: 91 SPN: 620 FMI: 1 Accelerator Position Sensor Circuit

Cummins ISB CM550 (1990-94) Fault Code: 443 PID: SID 232 SPN: 620 FMI: 3 Accelerator Position Sensor Circuit

Cummins ISB CM550 (1990-94) Fault Code: 443 PID: 91 SPN: 620 FMI: 3 Accelerator Position Sensor Circuit

Cummins ISB CM550 (1990-94) Fault Code: 442 PID: 168 SPN: 168 FMI: 0 Unswitched Battery Supply Circuit

WARNING!