CAT 3406E (Prefix 1MM or 2WS) Fault Code: 28 PID: SPN: 91 FMI: 13 Throttle Sensor out of calibration

The ECM detects the following conditions:

•The duty cycle for the accelerator pedal position sensor is less than 5 percent or the duty cycle is greater than 95 percent for more than two seconds.
•The ECM has been powered for at least three seconds.

Probable Causes:

1) ECM Connection/Harness
2) Accelerator Position Sensor
3) Accelerator Position Sensor Harness
4) ECM Failure