Electronic Control System Signature, ISX and QSX15 Engines – FAULT CODE 394

Actuator Circuit


Fault Code: 394
PID: S020
SPN: 635
FMI: 5/5
LAMP: Yellow

Low current or open circuit detected at front timing actuator circuit.

Engine is run using
only the rear three cylinders.

Front Timing Actuator Circuit

Circuit Description

The timing actuators are actuated by the electronic control module (ECM) to control fuel metering. Each timing actuator is connected to the ECM by a supply and a return wire. An electrical pulse is sent to the timing actuator from the ECM on the supply wire and returns to the ECM on the return wire. Each solenoid valve is normally closed, and it is
only opened by an electrical pulse from the ECM during metering.

Component Location

The front timing actuator is mounted on the fuel delivery housing. It is the second actuator from the front of the engine.

Shop Talk

The possible failure modes are open circuit, short circuit to ground, high actuator resistance, and loss of boost voltage inside the ECM.

Refer to Troubleshooting Fault Code t05-394.

Last Modified:  26-Oct-2010