P0496: Evaporative Emission System High Purge Flow
What to do
Usually driveable. If the engine idles roughly or stalls just after filling up, mention that specifically — it points straight at the purge valve rather than a leak.
What this code means
More vapour is flowing from the canister into the intake than the module commanded, usually because the purge valve is not sealing when told to close. Carbon or debris on the valve seat is the common mechanism.
This is one of the few evaporative faults with a driveability consequence. A continuous vapour feed into the manifold behaves like a rich mixture the module did not ask for, giving a rough or surging idle and a stall on returning to idle — and it is worst immediately after refuelling, when the canister is fully loaded.
Likely causes
Start here
- Faulty EVAP purge valve · easy
- Leaking purge valve seal · easy
Less common
- Saturated charcoal canister · moderate
- Faulty fuel tank pressure sensor · moderate
Symptoms
Components involved
Information, not instruction
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Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
Community experience
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