PACCAR PX-6 CM2150 (2007-09) Fault Code: 431 PID: SID 230 SPN: 558 FMI: 2 Accelerator Pedal or Lever Idle Validation Circuit – Data Erratic, Intermittent, or Incorrect. Voltage detected simultaneously on both idle validation and off-idle validation switches.

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, recalibrate the ECM.

1)This fault code is usually caused by an open circuit on either the idle validation on-idle or the idle validation off-idle signal circuit, a loose connection, uncalibrated accelerator pedal or lever assembly, or miswired idle validation switch.
2)When installing a new accelerator pedal or lever assembly, it must be calibrated before operating the engine. To calibrate the new accelerator pedal or lever assembly, turn the keyswitch to the ON position and fully depress and release the pedal or lever three times.

Possible repairs:

1)Connect the ISS to the OEM harness.
2)Replace the ISS.
3)Replace the ECM.