The evaporative (EVAP) emission control system is designed to trap and hold volatile organic compounds (VOCs), such as carbon monoxide (CO) and nitrogen oxide (NOx). The EVAP system prevents these gasoline vapors from being released into the atmosphere while reducing the vehicle’s exhaust emissions.
The EVAP system has a vent valve that allows fresh air to enter the system. If the powertrain control module (PCM) detects a fault with the circuit controlling the vent or the system is venting when it shouldn’t, a code P0499 will be logged by on-board diagnostics (OBD).
What Does the P0499 Code Mean?
Diagnostic trouble code (DTC) P0499 stands for “Evaporative Emission System Vent Valve Control Circuit High.”
How an Evaporative Emission System Works
The EVAP system consists of hoses, valves, and a charcoal canister. To prevent vapors from being released into the atmosphere, they are routed into the charcoal canister, then into the intake airflow where they are burned in the engine.
As the canister purge solenoid valve opens, the manifold vacuum draws in the vapors from the canister. The same vacuum is applied to the pressure control valve. As the valve opens, fumes from the fuel tank are routed into the canister until it reaches the engine.
Once the valve closes, the pressure control valve is shut to keep vapors from escaping into the atmosphere.
The vent valve is normally open and is closed whenever the PCM tests the system. Because of the valve’s location, it is often subject to rust and corrosion. Once the PCM detects any problem with the EVAP system’s vent valve, it will log a P0499 code.
Note: The definition of code P0499 could be different depending on the vehicle manufacturer. Consult the appropriate repair manual or repair database for the exact code definition.
What are the Common Causes of the P0499 Code?
- EVAP vent valve failure
- Wiring issues
- PCM failure
What are the Common Symptoms of the P0499 Code?
How to Diagnose the P0499 Code?
P0499 is commonly stored in makes like Dodge, Honda, and Chevrolet, among others. While this DTC is considered a generic powertrain code, keep in mind that the steps for diagnosis and repair can vary depending on your vehicle’s specifications. If you’re not familiar with the process of diagnosing an EVAP system, it’s a good idea to bring your vehicle to a certified mechanic instead.
Here are some videos that show what the process might involve:
How to Fix the P0499 Code
Fixing a P0499 code can be frustrating and confusing if you don’t have the right tools and know-how for the job. Under these circumstances, it’s best to bring your vehicle to the nearest repair shop to ensure that the steps for repair are being followed correctly.
If you’re a seasoned DIYer who knows your way around trouble codes, you’ll know the importance of reading the repair manual before proceeding. Guides from those like Chilton or an ALLDATA subscription contain vehicle-specific repair information, so you might want to check those out before you start.
Where to Get a New EVAP System Vent Valve for Your Vehicle
Once you’ve identified that your EVAP system vent valve needs to be replaced, make sure to shop for a replacement right here at CarParts.com.
Our selection of direct-fit EVAP system vent valves has passed strict quality checks, ensuring that you’ll only get the best part for your ride. Choose from the top aftermarket brands today, and check out in a matter of minutes.
Use our website’s vehicle selector to narrow down the search results to products that match your car’s specifications. You can also reach our round-the-clock customer service representatives via our toll-free hotline to get further assistance when shopping.
Here at CarParts.com, you’ll never go over budget when shopping for replacement parts. All our products come with a low-price guarantee to help you get the best value for your money. We’ll deliver straight to your doorstep in as fast as two business days.
Check out our products today, and get your vehicle back on the road in no time with our high-quality EVAP system vent valves.
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