Emissions

P0497 — EVAP System Low Purge Flow

Severity: low Safe to drive

What P0497 means

The ECU opens the purge valve so fuel vapors stored in the charcoal canister are drawn into the intake and burned. P0497 sets when the flow during purge, judged mainly by the fuel tank pressure sensor, is lower than expected. Typical causes are a restricted line, a sticking purge valve or a kinked hose.

Symptoms

  • Check engine light on
  • Failed emissions or smog test
  • Possible fuel smell near the car
  • Fuel pump nozzle clicking off repeatedly while filling
  • Usually no noticeable change in engine behavior

Possible causes

  1. Sticking or weak purge solenoid valve
  2. Clogged or damaged charcoal canister
  3. Kinked, pinched or blocked purge hose
  4. Blocked EVAP line or tube
  5. Faulty canister vent valve
  6. Wiring or connector fault at the EVAP valves
  7. Faulty fuel tank pressure sensor

How to diagnose

  1. Scan for codes, review freeze frame data and see if the code returns after clearing
  2. Inspect the fuel cap for proper seating and a good seal
  3. Inspect EVAP hoses and lines for kinks, cracks and blockages
  4. Check power, ground and coil resistance at the purge valve and inspect the connector
  5. Command the purge valve on with a scan tool and confirm it clicks and passes air
  6. Test the canister vent valve operation
  7. Compare fuel tank pressure sensor readings during purge with expected values
  8. Smoke-test the EVAP system to find leaks and restrictions

Common fixes

  • Replace the purge valve
  • Replace or clear blocked hoses and lines and fix kinks
  • Replace the charcoal canister if clogged or damaged
  • Replace the canister vent valve
  • Repair the wiring or connector
  • Replace the fuel tank pressure sensor

Questions and answers

What does P0497 mean?

The ECU found that purge flow in the evaporative emission system is too low. The cause is usually the purge valve, hoses or the canister.

Can I drive with P0497?

Yes, usually, but do not put the repair off for long. The light will stay on, you may fail an emissions test, and a fuel smell is possible.

What should I check first?

Start with the fuel cap, then the purge hoses and the purge valve. A stuck valve or a pinched hose is often the culprit.

This is general information about the code. The meaning can differ between makes and models: a scan tool and the repair manual for your car will show the exact cause.