CM870 and ISX Engines – FAULT CODE 2312

Front Timing Actuator Circuit


Fault Code: 2312
PID: S20
SPN: 635
FMI: 11/31
LAMP: Amber

Timing Actuator Number 1 Circuit Error. Error detected on the front timing actuator circuit.

Cylinders in front bank will not receive fuel. Engine will run rough with low power.

Front Timing Actuator Circuit

Circuit Description

The timing actuators are commanded by the ECM to control fuel timing. Each timing actuator is connected to the ECM by a timing actuator (+) and timing actuator (-) wire. An electrical signal is sent to the timing actuator from the ECM on the (+) wire and is returned to the ECM on the (-) wire. Each actuator is normally closed, and it is only opened by an electrical pulse from the ECM during metering.

Component Location

The front timing actuator is located on the fuel control housing. It is the second actuator from the front of the engine. The fuel control housing is located on the intake side of the engine below the EGR mixer. Refer to Section E for a detailed component location view.

Shop Talk

Possible causes of this fault are:

  • Open circuit in the engine harness, connectors, or actuator
  • Short circuit to ground in the engine harness or actuator
  • Short circuit to voltage source in the engine harness
  • Low or high resistance in the actuator.

Refer to Troubleshooting Fault Code t05-2312

Last Modified:  01-Sep-2010