Cummins ISL CM850 (2003-06) Fault Code: 148 PID: 91 SPN: FMI: 0 Accelerator Pedal or Lever Position Sensor 1 – Data Valid but Above Normal Operational Range – Most Severe Level. A frequency of more than 1500 Hz has been detected at the frequency throttle input to the ECM.

The frequency throttle can be used in conjunction with a voltage throttle or by itself.

Possible causes:

1)Malfunctioning OEM Frequency Throttle
2)Shorted signal wire to voltage source.

Possible repairs:

1)Repair or replace the frequency throttle.
2)Replace the OEM harness.