#OBD Codes
P0496 – Evaporative emission control system flow during a non-purge condition
Technical definition
EVAP system high purge flow
What does P0496 mean?
Code P0496 means your car’s engine control unit (ECU) has detected a problem with the evaporative emission control (EVAP) system – a system designed to stop fuel vapors from escaping into the atmosphere. Specifically, it means the system is releasing fuel vapors when it shouldn’t.
The main goal of the EVAP system is to make your car more environmentally friendly. It traps fuel vapors in a charcoal canister and releases them into the engine to burn when needed – so they don’t pollute the air.
Here’s a simple layout of how the EVAP system works:
The basic scheme of the EVAP system
The purge valve manages this process. If it releases vapors at the wrong time, your vehicle will generate a P0496 code.
How serious is P0496?
Trouble P0496 won’t damage your vehicle or affect its performance. However, you could run into other headaches, like failing emission inspections or even getting fined.
Can I still drive with P0496?
Yes, P0496 isn’t a critical issue. You’ll still be able to drive your car without any noticeable problems.
However, there are some drawbacks. It can bump emissions slightly, lead to a failed emissions test, and trigger the check engine light. If you ignore it, that persistent check engine light might hide more serious problems later.
Symptoms of P0496
The most obvious clue is the check engine light. Sometimes, you might also smell fuel or notice your car idling roughly when the purge valve releases fuel vapors at the wrong time. Beyond that, there are usually no other noticeable symptoms.
Common causes of P0496
Most often, P0496 appears due to:
- Faulty purge solenoid valve
- Faulty vent valve
- Faulty EVAP or fuel tank pressure sensor
- EVAP system hose leak (a common problem in Hyundai vehicles)
- Clogged EVAP charcoal canister
- Faulty purge flow sensor (mostly in Kia and Mazda vehicles)
- Wire damage or poor electrical connections
- Short circuit (a common problem in Hyundai and Isuzu vehicles)
- Loose or damaged gas cap
How to troubleshoot P0496
Use these tips to diagnose and fix a P0496 code accurately:
Scan for other codes
Use an OBD scan tool to check for other related trouble codes, which may provide additional clues to the underlying problem. These include:
- P0442, P0455, and P0456: Indicate leaks in EVAP system
- P0441: Indicates EVAP incorrect purge flow
- P0442: Points to problems with the vent valve
- P0443-P0448: Indicate electrical issue with the purge control valve circuit
- P0450-P0454: These codes specifically relate to the EVAP pressure sensor.
- P0457: Indicates that the gas cap is loose or damaged
Clear the codes and test drive
Firstly, use your scan tool to clear the P0496 fault code from your car.
- If the fault code immediately reappears: This indicates the issue is ongoing. Skip the test drive and continue troubleshooting other potential causes.
- If the codes clear successfully: Drive your car for about 15 minutes to fully warm up the engine and observe its behavior.
After the test drive, perform another scan to see if the code reappears. If it does, this confirms the problem persists and requires further investigation.
Check the gas cap and seals
This one’s quick and easy. Although this isn’t the primary cause of the P0496 code, it is still common to see the same code when the gas cap isn’t sealing properly. Make sure that the gas cap is tight and undamaged.
Also, check the condition of the rubber O-ring and replace it if necessary. If you notice any dirt or debris on the gas cap or seal, clean it using WD-40.
Inspect for leaks with a smoke machine
A smoke test can help you spot leaks in the EVAP system and vacuum lines. By filling the system with smoke, you can easily see where it escapes, whether it’s from a cracked hose, a loose connection, or a broken canister.
Examine canister purge valve
If there are no leaks, it’s time to check the purge valve itself. You’ll usually find it in the engine bay or near the gas tank.
Purge valve. Source: reddit.com
To test it, start with a cold engine. Locate the purge valve, start the engine, disconnect the EVAP hose, and place your finger over the vacuum port. While the engine is cold, you shouldn’t feel any suction since the valve should stay closed at this stage.
After a few minutes, the valve should open as the engine warms up, and you should feel suction at the port.
If you feel suction from the start, the valve is likely stuck open. If there’s still no suction after warming up, it may be stuck closed. In either case, you’ll probably need to replace the valve.
Will a P0496 code clear itself?
Yes, but it may take a week or more to disappear after you fix the problem.
Disclaimer: Advice, how-to guides, and car care tips on our blog are intended as helpful resources for general maintenance and repairs. While we strive for accuracy, the information is provided to the best of our knowledge and should be used at your own discretion and risk.
Always refer to your vehicle's owner's manual or consult a certified mechanic for specific repair details and safety procedures.
Always refer to your vehicle's owner's manual or consult a certified mechanic for specific repair details and safety procedures.
