CM850 Electronic Control System – FAULT CODE 2349

  Printable Version

Overview

EGR Valve Control Circuit – Shorted High or Open SMALL | MEDIUM | LARGE

Circuit Description

The electronic control module (ECM) controls the EGR valve, opening and closing it based on various operating conditions. The EGR valve is opened and closed by a DC motor that receives voltage from the ECM on the EGR valve motor signal (+) and EGR valve motor signal (-) circuits. To open the valve, the motor receives voltage on the EGR valve motor signal (+) circuit. To close the valve, the motor receives voltage on the EGR valve motor signal
(-) circuit.

Component Location

The EGR valve motor is located on the exhaust side of the engine and is attached to the EGR valve assembly, which is mounted on the exhaust manifold. Refer to Procedure 100-002 for a detailed component location view.

Shop Talk

The ECM monitors the voltage level of this circuit and logs a fault code if the voltage level indicates an open circuit or if a short circuit to voltage source is present. This fault is always set inactive when the keyswitch is turned on. If the fault condition reoccurs while the keyswitch is in the ON position, the fault code will be set active. Since active faults are set inactive at key “ON,” this troubleshooting tree should be used to troubleshoot active and inactive faults. Possible causes of this fault include:

• EGR valve motor output (+) or (-) leads shorted to a voltage source in the engine harness or ECM
• An open circuit in the engine harness, connectors, motor, or ECM.

NOTE: Do not supply voltage of any kind to the EGR valve motor. This circuit uses a pulse-width-modulated signal and direct voltage can permanently damage the motor.

Refer to Troubleshooting Fault Code t05-2349