Symptoms of P0480
- 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 P0480
- 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 fuse, relay, control module, fan motor current draw, ground path, and connector condition.
- Command the fan with a scan tool if supported and compare command state with voltage and fan operation.
- Inspect related coolant temperature, air conditioning pressure, and system-voltage data that influence fan command.
Related OBD-II codes
These nearby emissions entries can help compare wording and pin down the fault area.