P0497 Evaporative Emission System Low Purge Flow

P0497 indicates low purge flow in the evaporative emission system. The controller commanded purge but did not see enough expected vapor flow or tank pressure response.

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 gas cap for P0497 without checking commanded purge flow, purge valve operation, and EVAP line restrictions.

Symptoms of P0497

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 P0497

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

Compare purge command, EVAP pressure response, fuel trims, purge flow data where available, fuel level, and freeze-frame operating conditions.
Inspect for a stuck-closed purge valve, restricted purge line, blocked charcoal canister, vent valve problems, disconnected hoses, and wiring faults.
Command purge with a scan tool and verify actual flow, pressure change, and idle or fuel-trim response.

Related OBD-II codes

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