VIN 6
DTC P0495 (LMM)
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (Diagnostic System Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Strategy Based Diagnosis) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (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 speed is greater than 1,700 RPM for greater than 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 (Diagrams)
Connector End View Reference
Component Connector End Views (Connector End Views By Name)
Description and Operation
Cooling Fan Description and Operation (with RPO LMM) (Cooling Fan (with VIN 6)) Cooling Fan Description and Operation (W/LGH) (Cooling Fan Description and Operation (with VIN L))
Electrical Information Reference
* Circuit Testing (Circuit Testing)
* Connector Repairs (Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (Wiring Repairs)
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions (Powertrain Diagnostic Trouble Code (DTC) Type Definitions)
Scan Tool Reference
Control Module References (Programming and Relearning) for scan tool information
Circuit/System Verification
1. Ignition OFF, verify the fan clutch is not seized or binding by turning the fan by hand.
2. Idle the engine.
3. Command the cooling fan clutch to 10 percent with a scan tool.
4. Operate the engine at 1,500 RPM for 2 minutes. The fan should be quiet to indicate the clutch is disengaged.
5. Command the cooling fan clutch to 80 percent, with a scan tool.
6. Operate the engine at 1,500 RPM for 2 minutes. Observe the difference between the scan tool Fan Speed and Desired Fan Speed parameters. The difference should remain less than 1,000 RPM throughout the speed transition.
7. Observe the DTC information with a scan tool. Verify DTC P0495 is not set.
8. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
Circuit/System Testing
1. Ignition OFF, disconnect the cooling fan clutch 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 cooling fan 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 (Verification Tests) after completing the diagnostic procedure.
* Fan Clutch Replacement (Service and Repair)
* Control Module References (Programming and Relearning) for ECM replacement, setup, and programming