P0493
Fan Overspeed
Fan Overspeed: the control module has detected this fault condition.
- Check engine light: Yes
- Emissions related: No
- Repair difficulty: medium
Common causes
Ordered by how often each turns out to be the cause.
- Fan relay welded closed - fan runs uncontrolledCommon
- PWM line shorted to supplyPossible
- Tachometer feedback miscalibratedLess likely
Parts involved
- Cooling Fan
- Fan Relay
- Fan Speed Sensor
P0493 is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.