Cummins ISX15 CM2250 (2010-12) Fault Code: 6263 PID: SPN: 647 FMI: 3 Fan Control Circuit- Voltage Above Normal or Shorted to High Source

Circuit Description
The fan control circuit is a device used by the engine to control the fan operation. When the engine control module (ECM) energizes the fan control circuit, the engine fan is engaged.

The fan control circuit utilizes a pulse width modulated (PWM) signal. A PWM signal is a pulsed voltage signal between 0 VDC and system voltage. The frequency of the pulsed voltage signal is dependent on the application requirements.

There are two types of fans supported by the fan control circuit; variable speed and ON/OFF. INSITE? electronic service tool can be used to determine which fan type is currently set up for use. The fan control circuit varies by original equipment manufacturer (OEM). Certain OEMs can use a solenoid return that is wired to the ECM or can use a return that goes to the engine block or chassis ground.

Component Location
The control solenoid location varies by OEM. Refer to the appropriate equipment manufacturer service information to determine the location.

Conditions for Running the Diagnostics
For ON/OFF and variable speed fan types, the diagnostic runs when the fan is turned OFF and will latch active when the fan PWM signal is 100 percent. For all other fan types, the diagnostic runs when the fan PWM signal is less than 100 percent and will latch active when the fan PWM signal is 100 percent.

Conditions for Setting the Fault Codes
The ECM detected the fan control circuit PWM signal voltage was greater then 0 VDC when the PWM signal was commanded OFF.

Action Taken When the Fault Code is Active
The ECM logs the fault code immediately when the diagnostic runs and fails.
Fan operation will be disabled.
Conditions for Clearing the Fault Code
To validate the repair, perform a key cycle, start the engine, and let it idle for 1 minute.
The fault code status displayed by INSITE? electronic service tool will change to INACTIVE immediately after the diagnostic runs and passes.
The Reset All Faults command in INSITE? electronic service tool can be used to clear active and inactive faults, as well as extinguish the malfunction indicator lamp for on-board diagnostics applications.

Shop Talk
If Fault Code 2377 is still active after completing all the steps in this fault code troubleshooting tree, consult the OEM service literature for procedures to check the fan clutch device for an open circuit or short circuit to ground.

Possible causes of this fault include:

An open circuit in the harness or fan control solenoid.
A short circuit to voltage source in the OEM harness.
A malfunctioning ECM.
Reference the appropriate OEM wiring diagram when troubleshooting circuits that utilize wiring supplied by the OEM.

Possible Cause:
1) Fan Control solenoid failure
2) OEM harness
3) ECM calibration