P0485 — Cooling fan power/ground — circuit fault

P0485: Cooling fan power/ground — circuit fault — what it means, the affected system and what to check before replacing parts.

Meaning, symptoms, causes and checks

The monitor for cooling fan power/ground reports a problem in the named circuit; an open, short or particular failed part is not established by the label alone. The fan number identifies a control channel; it does not establish the relay location or motor layout. Circuit faults and fan-speed faults are different conditions.

Affected system: Engine cooling fan control

Symptoms

  • Inactive fan; high temperature at idle.

Possible causes

  • Damaged wires, corroded contacts or blown fuse.

What to check

  • Inspect fan wires for breaks/shorts and check fuses.

Also written as: P0485-00, P048500, PO485 (some scan tools add the fault-type byte, e.g. -00).