What Does P0495 Mean?
The PCM has detected that the engine cooling fan speed exceeds the maximum expected RPM for the current operating conditions and fan speed command. Unlike P0493 which indicates a mechanically locked clutch, this code specifically reports that the fan is spinning faster than the PCM has commanded, suggesting a control system issue rather than a purely mechanical failure.
Common Causes
35%
Faulty fan speed control module or resistor pack providing higher voltage than commanded to the fan motor
30%
Shorted fan relay contacts welded closed, providing continuous full power to the fan motor regardless of PCM command
20%
Fan speed sensor reading incorrectly high due to electromagnetic interference or sensor malfunction
15%
PCM fan control output circuit shorted, sending maximum duty cycle signal to the fan controller
Diagnostic Steps
1
Monitor fan speed and PCM commanded fan duty cycle simultaneously on a scan tool. If the actual speed is significantly higher than the commanded speed, the fan control system is not responding to PCM commands properly.
2
Check the fan relay by swapping it with an identical relay. If the relay contacts are welded closed, the fan will run at full speed whenever the ignition is on. The relay should click when removed and the fan should stop.
3
For PWM-controlled fans, measure the duty cycle signal at the fan control module input. Compare the measured duty cycle to the PCM's commanded value. A mismatch indicates a wiring fault between PCM and controller.
4
Verify the fan speed sensor by comparing scan tool speed data to an independent measurement using a non-contact tachometer aimed at the fan blades. If they match, the overspeed is real; if not, the sensor is faulty.
5
Inspect the fan speed control module ground and power connections for corrosion or damage that could cause the module to default to maximum speed output.
Estimated Repair Cost
$100 - $450
Parts + labor, varies by vehicle and location
The PCM has detected that the engine cooling fan speed exceeds the maximum expected RPM for the current operating conditions and fan speed command. Unlike P0493 which indicates a mechanically locked clutch, this code specifically reports that the fan is spinning faster than the PCM has commanded, su...
The most common cause of P0495 (Fan Speed High) is: Faulty fan speed control module or resistor pack providing higher voltage than commanded to the fan motor
Typical repair costs for P0495 range from $100 to $450, depending on the vehicle, location, and whether you do it yourself or go to a shop.
A fan running faster than commanded wastes engine power and fuel, causes excessive cabin noise, and may prevent the engine from reaching optimal operating temperature. In extreme cold weather, overcooling could impair engine lubrication and increase emissions.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P0495 to identify the root cause.
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Quick Info
Category
Powertrain
System
Engine Cooling System
Difficulty
Type
Generic (SAE)
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