Fan Speed High - Bank 1
The P0495 code means the vehicle's onboard diagnostic system has detected: Fan Speed High - Bank 1. This is a low severity code.
- Keep driving?
- Yes, but fix soon
- DIY difficulty
- moderate
- Estimated cost
- $100 - $400 (parts and labor)
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Common Symptoms
- Check Engine Light on
- Cooling fan excessively loud
- Fan runs at high speed unnecessarily
- Possible overcooling
Probable Causes (Ranked by Likelihood)
- Fan control module stuck in high-speed output Very High
- Fan relay welded closed High
- Coolant temperature sensor reading higher than actual temperature Moderate
- Shorted wiring in fan speed control circuit Moderate
Frequently Asked Questions
Why is my cooling fan so loud with P0495?
P0495 indicates the fan is running at high speed when it should not be. The fan control system is unable to reduce fan speed to match cooling demand, so it runs at maximum speed creating excessive noise.
Can a stuck fan relay cause P0495?
Yes. A relay with welded contacts will keep the fan circuit energized at high speed regardless of ECM commands. Removing the relay will confirm this diagnosis if the fan stops.
Will P0495 affect fuel economy?
Yes, slightly. A constantly running high-speed fan places additional load on the electrical system, which increases alternator load and parasitic drag on the engine, reducing fuel economy.
Mechanics Guide Step-by-step diagnosis
Step-by-Step Diagnostic Procedure
-
Compare engine coolant temperature sensor reading to actual coolant temperature; if sensor reads high, replace it
-
Test the fan relay by removing it and checking if the fan stops; a welded relay will keep the fan running
-
Inspect the fan control module for signs of overheating or water damage
-
Use a scan tool to command different fan speeds and verify the system responds to lower speed commands
Sources 2
This page is built from documented references. Verify against your own service info before repair work.
- SAE J2012Diagnostic Trouble Code Definitions (defines the generic OBD-II code ranges)
- Cross-checked against the SAE J2012:2002 DTC table (2026-08-27)archived scan of the SAE standard — readable copy, not SAE’s current edition
Commonly Affected Vehicles
- 2008-2018 BMW X3
- 2010-2020 Mercedes-Benz GLC
- 2009-2019 Audi Q5
- 2011-2020 Volkswagen Tiguan
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