CM850 Electronic Control System - FAULT CODE 123

Intake Manifold Pressure Sensor Circuit – Voltage Below Normal or Shorted to Low Source

Overview

CODE

REASON

EFFECT

Fault Code: 123
PID: P102
SPN: 102
FMI: 4/4
LAMP: Amber
SRT:

Intake Manifold Pressure Sensor Circuit – Voltage Below Normal or Shorted to Low Source. Low signal voltage detected at the intake manifold pressure circuit.

Automotive: Derate in power output of the engine.

Marine:
None – No engine protection for circuit sensor failure.

Intake Manifold Pressure Sensor Circuit

SMALL | MEDIUM | LARGE

Circuit Description

The intake manifold pressure sensor monitors intake manifold pressure and passes information to the electronic control module (ECM) through the engine harness. On automotive applications, if the intake manifold pressure becomes too low, it will cause a derate condition.

For marine applications, no derate condition occurs. There is no engine protection for a circuit or sensor failure.

Component Location

The intake manifold pressure sensor is located in the air intake horn. Refer to Procedure 100-002 for a detailed component location view.

Shop Talk

The intake manifold pressure sensor shares supply and return wires in the engine harness with other sensors. Opens and shorts in the engine harness can cause multiple fault codes to be active. Before troubleshooting Fault Code 123, check for multiple faults.

Possible causes of this fault code include: