CM850 Electronic Control System – FAULT CODE 245

Fan Control Circuit – Voltage Below Normal or Shorted to Low Source


Fault Code: 245
PID: S033
SPN: 647
FMI: 4/4
LAMP: Amber

Fan Control Circuit – Voltage Below Normal or Shorted to Low Source. Low signal voltage detected at the fan control circuit when commanded on.

The fan can possibly stay on continuously or not run at all.

Fan Control Circuit

Circuit Description

The electronic control module (ECM) provides a signal to the fan control solenoid to turn the engine fan on and off. There are two types of fans supported by this signal; variable speed and ON/OFF. The INSITE™ electronic service tool can be used to determine which fan type is currently set up for use. The fan control circuit varies by OEM. Certain OEM’s may use a solenoid return that is wired to the ECM or may use a return that goes to engine block or chassis ground.

Component Location

The control solenoid location varies by OEM. Refer to the appropriate OEM service literature to determine the location.

Shop Talk

The fan control logic can be adjusted with the INSITE™ electronic service tool. There are two choices: 12 or 24 VDC ON, or 0 VDC ON. For proper fan operation, the fan control logic setup with INSITE™ electronic service tool must match the hardware configuration on the vehicle.

This fault code is logged when the ECM commands 12 or 24 VDC to the fan control solenoid, but the voltage on the fan control signal circuit is less than 12 or 24 VDC. The low voltage on the signal circuit usually indicates a short circuit to ground in the harness or solenoid.

If Fault Code 245 is still active after completing the following troubleshooting steps, consult the OEM service literature for procedures to check the fan control circuit for a short circuit to ground.

Refer to Troubleshooting Fault Code t05-245

Last Modified:  08-Jul-2010