P0495

DTC P0495

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions provides an overview of each diagnostic category.



DTC Descriptor
DTC P0495
- Cooling Fan Speed High




Diagnostic Fault Information






Circuit/System Description

The cooling fan relay sends a pulse width modulation (PWM) signal of 12-14 volts to the cooling fan by the cooling fan clutch supply voltage circuit. The engine control module (ECM) uses the PWM signal, which controls the speed of the cooling fan clutch by controlling the position of the oil control valve inside the clutch. If the cooling fan clutch RPM is too high when the control module is commanding 0 percent, DTC P0495 will set.


Conditions for Running the DTC

The engine is running.


Conditions for Setting the DTC

Cooling fan RPM exceeds 1,700 RPM for 90 seconds.


Action Taken When the DTC Sets

DTC P0495 is a Type C DTC.


Conditions for Clearing the DTC

DTC P0495 is a Type C DTC.


Reference Information
Schematic Reference

Engine Cooling Schematics ()
Connector End View Reference

Component Connector End Views
Electrical Information Reference

* Circuit Testing
* Connector Repairs
* Testing for Intermittent Conditions and Poor Connections
* Wiring Repairs

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference

Control Module References for scan tool information


Circuit/System Verification

Engine OFF, verify the fan clutch is not binding by turning the fan by hand.


Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the fan shroud.
2. Operate the engine at 1,500 RPM for 2 minutes. The fan should be quiet to indicate the clutch is disengaged.

• If disengaged, test or replace the relay.
• If not disengaged, test the cooling fan clutch supply voltage circuit for a short to voltage. If the circuit tests normal, replace the clutch.




Component Testing


Relay Test
1. Connect the relay ground terminal to ground and the voltage supply terminal to appropriately fused power to energize the relay.
2. Test for less than 1 volt between the load voltage supply terminal and ground.
3. Connect the relay control circuit terminal to ground.
4. Test for B+ between the load voltage supply terminal and ground.



Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

* Fan Clutch Replacement (Service and Repair)
* Control Module References for ECM replacement, setup, and programming