Cummins ISL CM850 (2003-06) Fault Code: 443 PID: SID 221 SPN: 1043 FMI: 4 Accelerator Pedal or Lever Position Sensor Supply Voltage Circuit – Voltage Below Normal or Shorted to Low Source. Low voltage detected at sensor supply circuit to the accelerator pedal or lever position sensor.

Low voltage on the +5 VDC supply line can be caused by a short circuit to ground in the supply line, a short circuit between the supply line and return circuit, a failed accelerator, or a failed ECM power supply.

Possible repairs:

1)Replace the accelerator pedal or lever position sensor.
2)Repair or replace the OEM harness.