P0496 Evaporative Emission System High Purge Flow

P0496 points to high purge flow in the evaporative-emissions system. The engine may be drawing purge vapor when the module expects little or no purge flow.

Code details

Generic OBD-II · P0

System: Emissions
Code type: Generic (SAE / ISO controlled)
Standard: SAE J2012 / ISO 15031-6

Diagnostic boundary

A diagnostic trouble code reports that a monitored test failed. It does not prove one specific part is bad, and manufacturer logic can add vehicle-specific conditions.

Do not replace the canister before testing purge-valve sealing; excessive purge flow often starts with a valve that leaks when closed.

Symptoms of P0496

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 P0496

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 whether the purge valve is stuck open, leaking, incorrectly commanded, or affected by hose routing problems.
Watch fuel trims and idle quality while commanding purge on and off if the scan tool supports bidirectional control.
Inspect EVAP plumbing, canister condition, purge solenoid wiring, and symptoms such as hard starting after refueling.

Related OBD-II codes

These nearby emissions entries can help compare wording and pin down the fault area.