Symptoms of P0484
- Check-engine light, often with no obvious change in how the car drives.
- A failed emissions test or incomplete readiness monitors.
- Sometimes a faint fuel-vapour smell (on EVAP codes).
Common causes of P0484
- A worn catalytic converter or an oxygen/air-fuel sensor reading out of range.
- EVAP leaks — a loose or failed gas cap, cracked hose, or purge/vent valve.
- Exhaust leaks, fuel-trim problems, or a fault in a related monitor.
Useful checks before replacing parts
- Check fan current draw, command state, fuse behavior, fan motor condition, relay or module temperature, and freeze-frame coolant temperature.
- Inspect for seized fan blades, worn motor bearings, shorted wiring, melted connectors, water intrusion, and harness contact with sharp or hot parts.
- Measure current during low and high speed commands to determine whether the load or wiring is causing the over-current.
Related OBD-II codes
These nearby emissions entries can help compare wording and pin down the fault area.