P0496 Code: EVAP High Purge Flow — Causes & Fix
P0496 means the evaporative emissions (EVAP) system is showing high purge flow — vapour is being drawn in when it should not be, often a stuck-open purge valve.
- Applies to
- All OBD-II vehicles (any make or model)
- Est. repair cost
- $30 – $350
- Time to fix
- 30 minutes – 2 hours
What it means
The usual cause is a purge valve stuck open; others are a vent valve fault or wiring issues. P0496 is a generic OBD-II powertrain code defined in the SAE J2012 standard, so it applies to virtually any 1996-or-newer petrol car or light truck regardless of make. Fix the underlying fault, then clear the code with an OBD-II scan tool — it will return if the problem isn't resolved.
Symptoms
- Check engine light on
- Rough or stalling idle (extra vapour)
- Hard starting after refuelling
How to fix it
- 1
Test the purge valve
1. Check that the purge valve holds vacuum and closes fully. 2. Replace a stuck-open valve.
- 2
Verify the vent side
1. Check the vent valve and lines. 2. Repair, then clear the code.
Frequently asked questions
Why does my car stall at idle with P0496?
A purge valve stuck open dumps extra fuel vapour into the intake at idle, which can cause stalling. Replacing the valve usually fixes it.
Last updated July 19, 2026
Guidance only — always consult a qualified professional or the official service manual before carrying out repairs.