Symptoms of P0468
- 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 P0468
- 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
- Review purge flow sensor voltage, reference voltage, ground path, purge command, freeze-frame conditions, and other high-input sensor codes.
- Inspect for open grounds, short-to-voltage faults, connector corrosion, sensor internal failure, and harness damage near heat or moving parts.
- Command purge while watching the signal to see whether it is stuck high or reacts incorrectly to flow changes.
Related OBD-II codes
These nearby emissions entries can help compare wording and pin down the fault area.