OBD-II Code P0495 — What It Means & How to Fix It

What Does This Error Mean?

P0495 means the cooling fan is spinning faster than the PCM commanded. This is the opposite of P0494, which is a fan running too slow. A fan running at excessive speed usually points to the fan control module not properly limiting fan speed, or a wiring problem causing the fan to receive a constant high-speed signal. While overheating is not the concern here, excessive fan speed damages bearings and wastes electrical power.

Affected Models

Vehicles with variable-speed or PWM-controlled cooling fans
Common on GM models with electric fan control modules
Ford vehicles with electronically controlled fan assemblies
European vehicles with sophisticated fan speed management systems
Hybrid vehicles where the cooling fan has a dedicated speed controller

Common Causes

Fan control module has failed and is sending maximum power to the fan continuously
PWM control signal wire from the PCM to the module is shorted, causing a full-speed command
Fan motor has an internal fault bypassing the speed control input
A/C high-pressure switch or signal is stuck in a state that commands full fan speed at all times
Fan speed feedback signal wire is giving incorrect readings, making the PCM think the fan is always running slow

How to Fix It

Use a scan tool to observe commanded fan speed versus actual fan speed. If the PCM commands a low percentage but the fan runs at 100%, the fault is downstream of the PCM — either the module or the wiring.

If the PCM itself is commanding 100% continuously (even when the engine is cool), the PCM's logic or a sensor input may be at fault.
Disconnect the PWM control signal wire at the fan control module. If the fan immediately slows down or stops, the module's internal fault is confirmed — it was ignoring the PWM input and running at full speed on its own.

With the control wire disconnected, most fan modules should default to low speed or off, not high speed.
Inspect the A/C high-pressure switch and the A/C request signal going to the cooling fan circuit. An A/C switch stuck in the high-pressure tripped position can continuously command maximum fan speed.

Check A/C system pressure — an overcharged A/C system will repeatedly trigger the high-pressure fan speed command.
Check the fan speed feedback wire for damage. If this wire is shorted to ground, the PCM may receive a signal suggesting the fan is always running slowly, so it keeps commanding more speed — causing the module to run the fan too fast.

This scenario creates a loop: the PCM keeps commanding more speed because it thinks the fan is slow, which makes the fan run even faster.
If all wiring and signals check out, replace the fan control module. This is the most likely culprit when the fan consistently runs faster than commanded with no obvious electrical fault.

After replacement, verify the fan responds correctly to different commanded speeds: low speed at moderate temperature, high speed when A/C is on or when the engine is hot.

When to Call a Professional

Fan control module replacement resolves most P0495 cases. If wiring is involved, a shop with a wiring diagram can trace and repair the fault in 1 to 2 hours. Total repair cost typically ranges from $100 to $500.

Frequently Asked Questions

Is it dangerous to drive with the cooling fan running at full speed all the time?

Not immediately dangerous for the engine — full speed means very effective cooling. But it is hard on the fan motor and bearings, which will wear out prematurely. It also draws excess electrical current, which stresses the alternator and battery. Fix it within a reasonable timeframe.

My car sounds like a jet at idle — could P0495 be why?

Yes — a cooling fan stuck at full speed is quite loud, especially at idle. If your car suddenly sounds much louder than usual when idling, and the temperature is normal, a stuck-on cooling fan is a very common culprit.

Can P0495 drain my battery?

Over time, yes. An electric cooling fan running continuously at full speed draws significant current — often 20 to 40 amps. This puts extra load on the alternator. In a worst case where the fan runs even with the engine off, it can drain the battery within hours.