P0496🔧 Evaporative emissions (EVAP)Usually OK to drive

P0496: EVAP System High Purge Flow (Meaning, Causes, Fixes)

Reviewed 2026-10-22 · Based on 2 cited source(s)

What P0496 means

The evaporative emission (EVAP) system stores fuel vapor from the gas tank in a charcoal canister and later lets the engine burn it, using a purge valve between the canister and the intake. OBD-Codes.com explains that to test the system, the engine computer closes the purge valve and the vent valve to seal it, then watches the fuel tank pressure sensor. If it sees more vacuum than expected within a set time, meaning engine vacuum is still being drawn into the system, it sets P0496. RepairPal describes it the same way: the PCM detects the EVAP system purging when it should not. It is a generic OBD-II code. OBD-Codes.com names it 'EVAP Flow During a Non-Purge Condition' and says it is most common on GM vehicles (Chevrolet, Pontiac and others), while Acura, Honda, Hyundai, Kia and Mazda call it 'EVAP System High Purge Flow', which RepairPal also uses. P0497 is the matching low purge flow code.

Severity: can I keep driving?

Usually OK to drive

Usually safe to drive in the short term, but get it fixed. RepairPal rates P0496 Moderate, meaning it may not threaten safety right away but should be diagnosed within a reasonable time. OBD-Codes.com says most drivers notice nothing beyond the check engine light, though some get hard starting, and an engine running rich for a long time can damage the catalytic converter. A stuck-open purge valve can also make the car fail an emissions inspection.

Common symptoms

Likely causes

Roughly most to least common, based on the sources below. Your vehicle may differ.

  1. Faulty EVAP canister purge solenoid valve stuck open or leaking (both sources; OBD-Codes.com says replacing it is the most common fix)
  2. Faulty EVAP vent solenoid or valve (OBD-Codes.com)
  3. Plugged or blocked EVAP charcoal canister (OBD-Codes.com)
  4. Failed fuel tank pressure (EVAP pressure) sensor (OBD-Codes.com; RepairPal lists replacing it as a common repair)
  5. Wiring problems, such as a poor connection or a short circuit (both sources)
  6. Leaking EVAP hose (OBD-Codes.com, noted for Hyundai) or a faulty purge flow sensor (OBD-Codes.com, noted for Kia and Mazda)
  7. Rarely, a failed powertrain control module (PCM) (RepairPal)

Diagnostic steps you can do

⚠ Before you start

Work on a cool engine, parked on level ground with the parking brake set. Never work under a car supported only by a jack.

  1. Read all stored codes and look for other EVAP codes, which can point to the same part.
  2. Find the purge solenoid valve (usually on or near the intake, in the hose that runs back to the charcoal canister) and check its hoses and electrical connector.
  3. OBD-Codes.com describes a simple test: disconnect the canister-side hose at the purge valve, unplug the valve's connector, start the engine and feel the valve's open port. If you feel vacuum with the valve unplugged, it is stuck open and needs replacing.
  4. Alternatively, remove the purge valve and blow through it. It is normally closed, so if air passes through with no power applied, OBD-Codes.com says to replace it.
  5. Clear the code after any repair and drive normally for a few days; EVAP tests only run under certain conditions, so the code can take a while to return if the problem isn't fixed.

Typical fixes

Repair costs vary widely by vehicle, region, parts brand and shop, so we don't quote prices. Get a written estimate after diagnosis.

🛠 When to call a pro

  • Confirming the fault needs an advanced scan tool that can seal the EVAP system and read fuel tank pressure, as OBD-Codes.com describes
  • The purge valve tests good, which OBD-Codes.com says points to an intermittent valve problem or the fuel tank pressure sensor
  • The code keeps coming back after you've replaced the purge valve
  • You have an emissions inspection coming up and need the EVAP monitor to complete

Where to buy

Plain search links. Always match parts to your exact year, make, model and engine.

OBD2 scanners on Amazon Parts at Advance Auto Parts catalog at RockAuto

FAQs

Is P0496 serious?

Not usually right away. RepairPal rates it Moderate, and OBD-Codes.com says the check engine light is often the only symptom. Left alone, a stuck-open purge valve can cause hard starts and a rich-running engine that may eventually hurt the catalytic converter, so fix it reasonably soon.

What is the most common fix for P0496?

OBD-Codes.com says replacing the EVAP purge solenoid valve is the most common fix, but recommends testing it first. RepairPal also lists purge solenoid failure first, and lists replacing the fuel tank pressure sensor as a common repair.

Is P0496 different from P0497?

Yes. P0496 means high purge flow (vapor flowing when it shouldn't), while P0497 means low purge flow, per RepairPal's code list.

How much does it cost to fix P0496?

Neither source gives a repair cost. The price depends on which part has failed, so get a diagnosis or a written estimate before replacing parts.

Sources

  1. OBD-Codes.com: P0496 EVAP Flow During A Non-Purge Condition
  2. RepairPal: P0496 Evaporative Emission System High Purge Flow (rated Moderate)

Last reviewed 2026-10-22. Code definitions and repair steps can vary by manufacturer. Confirm with your vehicle's service information.