CM850 Electronic Control System – FAULT CODE 272 (ISB/QSB (Automotive and Industrial Application)

High Fuel Pressure Solenoid Valve Circuit – Voltage Above Normal or Shorted to High Source


Overview

CODE REASON EFFECT
Fault Code: 272
PID: S126
SPN: 1347
FMI: 3
LAMP: Amber
SRT: 

High Fuel Pressure Solenoid Valve Circuit – Voltage Above Normal or Shorted to High Source. Electronic fuel control actuator shorted high.

Engine will run poorly but will be severely derated. Rail pressure will be higher than commanded.

Electronic Fuel Control Actuator Circuit
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Circuit Description

The circuit is a pulse width modulated (PWM) driver in the Electronic Control Module (ECM) that controls the electronic fuel control actuator. The actuator is grounded in the ECM. The actuator is a normally open. Pulse width modulation (PWM) duty cycle to the electronic fuel control actuator depends on the difference between desired rail pressure and sensed rail pressure. Duty cycle will also decrease (electronic fuel control actuator opens) as fueling increases.

Component Location

The electronic fuel control actuator is located on engine-mounted fuel pump housing. The engine wiring harness and the ECM are other components in the circuit that can cause this fault code. Refer to Procedure 100-002 for a detailed component location view.

Shop Talk

This fault becomes active when the ECM detects an open in the electronic fuel control actuator circuit. Causes of this fault code are a short circuit to a positive voltage or an open circuit in the electronic fuel control actuator circuit. If there is high harness resistance, Fault Code 2311 could have high inactive counts. If the fault code is intermittent, look for causes of an intermittent open circuit such as loose pins and bad connections.

Refer to Troubleshooting Fault Code t05-272

Last Modified:  08-Jul-2010