P0495 code meaning
Fan 1 Overspeed
Powertrain system Generic code P04xx codes Check engine light
What P0495 means
Two kinds of cooling fan carry these codes: electric fans switched by relays or driven by a PWM/LIN fan module with speed feedback, and engine-driven fans with an electronically controlled viscous clutch, whose speed a Hall sensor reports – GM calls them EV fans, meaning electro-viscous, not electric vehicle. P0495 mainly concerns viscous fans: with the fan commanded off it turns faster than the permitted drag speed, so the clutch does not release. GM thresholds: Duramax 2016 above 1500 rpm, Duramax 2018 above a calculated drag speed, gasoline SUVs of 2004–05 above 1600 rpm without command – all with the warning lamp after two trips; Ford's 6.7-litre Super Duty uses it the same way. On GM's 2020 2.0-litre turbo with a LIN electric fan it means a reported speed above 2900 rpm.
P0495 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modeNot expected
- Repair difficultyMedium, DIY possible
- Typical labor1 to 3 hours
- Clears after repairAfter a drive cycle
Symptoms of P0495
- Check engine light on
- Loud fan roar even with a cold engine or at idle
- Slightly higher consumption, longer warm-up
Common causes of P0495
- Most likelyViscous clutch does not release (gummed, overfilled, seized)
- PossibleClutch solenoid or its control stuck open (short to positive, valve sticking)
- PossibleWrong speed signal (sensor, wiring, interference)
- Less likelyElectric fan: module runs uncontrolled at full speed or relay sticking
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Fan clutchCooling fan 1Fan speed sensorEngine control module
What each part of P0495 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 4 | Area: auxiliary emission controls (catalytic converter, EGR, EVAP). |
| 95 | The exact fault in that area. |
What to do next
- Note P0495 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P0495
What does P0495 mean?
P0495 means "Fan 1 Overspeed". Two kinds of cooling fan carry these codes: electric fans switched by relays or driven by a PWM/LIN fan module with speed feedback, and engine-driven fans with an electronically controlled viscous clutch, whose speed a Hall sensor reports – GM calls them EV fans, meaning electro-viscous, not electric vehicle. It is a generic code, so it means the same on every make.
Is it safe to drive with P0495?
Usually yes, for a short time, if the check engine light is steady and the car drives normally. If the light flashes or the car runs badly, stop and have it checked.
Will P0495 fail an emissions test?
Yes, it can. P0495 is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P0495 to fix?
Difficulty: medium. A typical repair takes 1 to 3 hours of work. A careful DIY repair is possible with basic tools and a scanner.
Will P0495 clear itself after the repair?
After the repair the car has to complete a drive cycle (a mix of city and highway driving) before the test runs again. Until then the readiness monitor shows "not ready", which can fail an inspection.