P0496Generic code

P0496 Code: Evaporative Emission System High Purge Flow

The P0496 code means more vapor from the canister is getting into the engine than the computer expects, almost always because a purge valve is stuck open. It causes hard starting after you fill the tank. It is a low severity code and you can keep driving.

Severity
Low
Can I keep driving?
Yes, no immediate risk
Estimated cost
$30 to $400
Difficulty
Easy
System
Emissions Control
Applies to
All OBD2 vehicles

Updated Reviewed by Renzo Chacca

On this page

What the P0496 code means

The purge valve is supposed to be closed with a cold engine and at idle right after startup. If the computer sees vacuum in the fuel tank when the purge should be closed, it concludes that the valve is letting air through and stores the P0496 code.

With the purge open, after you fuel up the gasoline and its vapors go straight into the engine. Starting takes longer and the idle is unstable for the first few seconds.

A purge valve that is stuck open can also saturate the canister with liquid gasoline. If that happened, replace the canister at the same time.

A simple way to check the valve is to disconnect the hose that goes to the canister with the engine idling cold: there should be no suction. If there is suction, the valve is open when it should not be. After you replace it, do not fill the tank past the first click of the pump nozzle, because liquid gasoline getting into the canister is what usually damages the valve.

P0496 code symptoms

  • Hard or long starting after fueling.
  • Unstable idle at startup.
  • Check engine light on.

Likely causes of the P0496 code

  1. Purge valve stuck open. This is the most frequent cause.
  2. Activated charcoal from the canister inside the valve. The granules keep the valve from closing.
  3. Canister saturated with liquid gasoline from overfilling the tank.

How to diagnose the P0496 code step by step

  1. With the engine off, blow through the purge valve. No air should pass.
  2. Watch the tank pressure with the engine idling. With the purge closed there should be no vacuum.
  3. Inspect the canister for liquid gasoline or loose charcoal.
  4. With the engine idling cold, disconnect the hose at the canister. There should be no suction.

How to fix the P0496 code

  • Replace the purge valve.
  • Replace the canister if it is saturated.
  • Clear the code and verify the repair.

Technical reference data

  • Purge valve: closed at rest.
  • Reference values: check the manufacturer data for your engine.

Brand-specific notes

This code is very common on some makes, and in every case the purge valve is an inexpensive part.

P0496 on GM

The P0496 code is very common on GM vehicles, and the valve is cheap.

P0496 on Chevrolet

The P0496 code is very common on Chevrolet vehicles, and the valve is cheap.

P0496 on Hyundai

The P0496 code is very common on Hyundai vehicles, and the valve is cheap.

Frequently asked questions about P0496

What does the P0496 code mean?
It means too much vapor from the canister is reaching the engine. The usual reason is a purge valve that is stuck open and lets vapors in when it should be closed.
Can I drive with a P0496 code?
Yes. It is a low severity code, although the engine will start poorly after you fill the tank.
Why does it start poorly after fueling?
Because the vapors go straight into the engine through the open purge valve. That makes the starting take longer and the idle rough for the first few seconds.
Is the repair expensive?
Normally not. The purge valve is an inexpensive part, and replacing it is usually a simple job.
How much does it cost to fix P0496?
Between $30 and $400. The low end is a purge valve alone, and the high end adds labor or a canister replacement.
What is the most common cause of P0496?
A purge valve stuck in the open position. Charcoal granules from the canister getting inside the valve, or a canister soaked with liquid gasoline from overfilling, come next.

Related codes

Questions about the P0496 code

There are no questions about this code yet. Tell us about your case: vehicle, symptoms and what you have already checked.