Powertrain
generic / SAE
P0494
Fan 1 Underspeed
Cooling fan 1 is rotating slower than commanded. The ECU sees the tachometer feedback below the expected window for the requested duty cycle - usually a worn fan motor, a high-resistance harness or feed, or a partially seized impeller.
SystemPowertrain
Typegeneric / SAE
GroupP0
Range / number4 / 94
Possible causes
- Fan 1 motor worn or brushes degraded high
- High contact resistance in feed medium
- Fan impeller seized or blocked low
Inspection / repair
- Difficulty: medium
- DIY: possible
- Estimated cost: 120–500 €
- Estimated time: 0.8–2 h
- Component: cooling fan 1
- Component: fan motor 1
- Component: fan speed sensor 1
- MIL / check engine light
Sources
References
sae:J2012