CM850 Electronic Control System – FAULT CODE 431 (NISS)

Accelerator Pedal or Lever Idle Validation Circuit – Data Erratic, Intermittent, or Incorrect


Overview

CODE REASON EFFECT
Fault Code: 431
PID: S230
SPN: 558
FMI: 2/2
LAMP: Amber
SRT: 

Accelerator Pedal or Lever Idle Validation Circuit – Data Erratic, Intermittent, or Incorrect. Voltage detected simultaneously on both idle validation and off-idle validation switches.

Automotive: Engine will only idle.

Marine: Severe derate in engine speed. Limp home capability only.

Accelerator Pedal or Lever Idle Validation Circuit
SMALL | MEDIUM | LARGE

Circuit Description

The idle validation switch is used by the electronic control module (ECM) to indicate when the accelerator pedal or lever is released (on-idle) or depressed (off-idle). The switch is adjusted at the factory to switch from on-idle to off-idle at the correct accelerator pedal or lever position.

Component Location

The nonintegrated sensor switch (NISS) is located on the accelerator pedal or lever assembly.

Shop Talk

  • This fault code is usually caused by an open circuit on either the idle validation on-idle or off-idle signal circuits, a loose connection, uncalibrated accelerator pedal or lever assembly, or miswired idle validation switch.
  • The nonintegrated sensor switch has a different internal resistance specification (10 ohms) than the integrated sensor switch (ISS).
  • When installing a new accelerator pedal or lever assembly, it must be calibrated before operating the engine. To calibrate, turn the keyswitch to ON position and fully depress and release the pedal or lever three times.

Refer to Troubleshooting Fault Code t05-431

Last Modified:  08-Jul-2010