P0495: The cooling fan is running faster than the computer expects

Fan speed high / fan 1 overspeed

Severity: Inspect soon

KBB lists constantly running fans, an overheating-looking temperature gauge and possible A/C disablement as signs, so the cooling system should be checked soon rather than ignored.

It gets more serious if:

Stop: Stop driving and let the engine cool if the temperature gauge moves into the hot zone.

Source: how we rate severity

P0495 in short

P0495 means the cooling fan is turning faster than the computer commands. A faulty fan or fan clutch, a bad fan relay, or wiring faults are the usual causes. The fan may run all the time, so get it checked soon and stop if the temperature gauge reads hot.

The engine computer commands the cooling fan to a speed and watches how fast it actually turns. P0495 sets when the fan speed is higher than commanded, or the fan will not drop back from high speed.

KBB lists a faulty fan or electro-viscous fan clutch, a bad fan relay, wiring or corroded connections, and less commonly a weak battery or computer fault. TroubleCodes.net lists wiring, the relay, the fan motor and a mechanical fault.

Ford has a bulletin for 2016-2019 F-Super Duty trucks with the 6.7L engine where the fan stays on or does not work and P0495 is among several fan codes. It points to an updated pinpoint test to avoid replacing the fan clutch unnecessarily.

Most likely causes

Cause 1: Faulty cooling fan motor or electro-viscous fan clutch
Common general cause
Why it ranks here
KBB lists the fan or fan clutch first, and TroubleCodes.net lists the fan motor and a mechanical fault.
What would change this
Rises if the fan runs at full speed from a cold start regardless of temperature. Falls if the fan follows commands normally.
Cause 2: Cooling fan relay stuck or failing
Common general cause
Why it ranks here
Both KBB and TroubleCodes.net list the fan relay; a relay stuck on keeps the fan running fast.
What would change this
Rises if the fan runs with the key off or the relay clicks stuck. Falls if swapping in a known good relay changes nothing.
How to test the underhood fuse block (engine compartment fuse box)
Cause 3: Wiring faults or corroded connectors
Common general cause
Why it ranks here
Both sources list wiring, water damage or corroded connections.
What would change this
Rises if the fan connector or harness shows damage or corrosion. Falls if wiring tests good.
Cause 4: Weak battery or engine computer fault
Possible — needs testing
Why it ranks here
KBB calls these less common, so they rank last.
What would change this
Rises if battery voltage is low or all other causes are cleared. Falls if the battery tests good.
How to test the engine control module (ecm / pcm)
Cause 5: Cooling fan fault on 2016-2019 Ford Super Duty 6.7L
Supported by vehicle data
Why it ranks here
Ford SSM 47999 lists P0495 with other fan codes for the 6.7L Super Duty and says an updated pinpoint test avoids unnecessary fan clutch replacement.
What would change this
Rises on the listed trucks if the dealer's pinpoint test finds a fault. Falls on other vehicles.

What to test first

Start at step 1. Each result tells you what it means and where to go next.

Step 1: Read all stored codes and note other fan codes such as P0480; check whether the fan runs at full speed on a cold engine.
Low riskTool: OBD-II scan tool
- IfThe fan runs hard on a cold start or with the key off
  It meansA stuck relay, fan clutch or command fault is likely.
  Go to step 2
- IfThe fan behaves normally and the code is stored in history
  It meansThe fault may be intermittent; check wiring.
  Go to step 2
Step 2: Find the fan relay in the underhood fuse box, listen for it sticking, and with the key off inspect the relay and fan connectors for damage or corrosion.
Use cautionTool: flashlight
Warning:Keep hands away from the fan: electric fans can start on their own even with the engine off.
- IfThe relay is stuck or the connector is corroded
  It meansReplace or clean it and recheck.
  Points to: Cooling fan relay stuck or failing
- IfRelay and wiring look good
  It meansHave the fan and its control tested by a shop.
  Go to step 3
Step 3: Have a shop command the fan with a bidirectional scan tool and test the fan, clutch and control signal, using the maker's pinpoint test where one exists.
Best left to a shopTool: bidirectional scan tool
Warning:A running cooling fan can cause injury and the engine and coolant can be hot; leave this to a shop.
- IfThe fan or clutch runs at full speed when commanded low
  It meansThe fan or fan clutch is faulty.
  Points to: Faulty cooling fan motor or electro-viscous fan clutch
- IfThis is a 2016-2019 Super Duty 6.7L
  It meansFollow Ford's updated pinpoint test AH.
  Points to: Cooling fan fault on 2016-2019 Ford Super Duty 6.7L

Symptoms

Cooling fan runs constantly or loudly
Check engine light on
Poor fuel economy
Temperature gauge climbing Gets more serious: stop and have it checked.

How to fix

Parts and cost context

Underhood fuse block (engine compartment fuse box):Relays are the cheapest item to test by swapping with a matching relay. Labour varies; get a quote.

Labor varies by vehicle and shop; get a quote before you approve a repair.

Compare used part prices on PartPriceGuide

On your vehicle

Ford

2016–2019 · F-250 Super Duty · 6.7L
Supported by vehicle data
Ford's bulletin lists P0495 with other fan codes when the fan stays on or does not work, and points to an updated pinpoint test.
2016–2019 · F-350 Super Duty · 6.7L
Supported by vehicle data
Same Ford bulletin covers the F-350.

SSM 47999 (f-250-super-duty)Status unverified
Cooling fan on or inoperative, fan DTCs including P0495
2016–2019f-250-super-duty · issued June 7, 2019 · NHTSA 10160939
Use the updated pinpoint test AH to avoid unnecessary fan clutch replacement on 6.7L trucks.
We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.
SSM 47999 (f-350-super-duty)Status unverified
Cooling fan on or inoperative, fan DTCs including P0495
2016–2019f-350-super-duty · issued June 7, 2019 · NHTSA 10160939
Use the updated pinpoint test AH to avoid unnecessary fan clutch replacement on 6.7L trucks.
We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

All Engine cooling (thermostat) codes

Sources and review

P0495 OBD-II trouble code — Kelley Blue Book
P0495 code definition and diagnosis — TroubleCodes.net
Ford SSM 47999: cooling fan stays on or is inoperative, DTCs P0480, P0494, P0495, P0529 and others (2016-2019 F-Super Duty 6.7L) — Ford Motor Company / NHTSA , June 7, 2019

Last reviewed: October 16, 2026
Written by: Saurabh K.
Editorial review: Pending
Technician review: Technician review pending

This page explains what a code usually means; it is not a substitute for a professional inspection. How we source and review · Report an error

Severity: Inspect soon

Most likely causes

Cause 1: Faulty cooling fan motor or electro-viscous fan clutch

Cause 2: Cooling fan relay stuck or failing

Cause 3: Wiring faults or corroded connectors

Cause 4: Weak battery or engine computer fault

Cause 5: Cooling fan fault on 2016-2019 Ford Super Duty 6.7L

What to test first

Step 1: Read all stored codes and note other fan codes such as P0480; check whether the fan runs at full speed on a cold engine.

Step 2: Find the fan relay in the underhood fuse box, listen for it sticking, and with the key off inspect the relay and fan connectors for damage or corrosion.

Step 3: Have a shop command the fan with a bidirectional scan tool and test the fan, clutch and control signal, using the maker's pinpoint test where one exists.