Maintenance Tips, Tricks And Hacks For Your Vehicle

P0496 OBD-II Evaporative Emission System High Purge Flow Trouble Code




The P0496 code is an OBD-II trouble code that stands for “Evaporative Emission System High Purge Flow and is triggered when the vehicle’s computer detects an excessive vacuum flow into the EVAP system.

This is a generic code relevant to many car manufacturers, however, it appears to be more popular in GM vehicles.

In this article, I will be talking about the P0496 trouble code, its symptoms, causes, and how to fix it.

What Does The P0496 Code Mean?

P0496 OBD-II Evaporative Emission System High Purge Flow Trouble Code

The P0496 trouble code means that the intake vacuum flow into the EVAP system is excessive. When the vacuum in the EVAP system exceeds the predefined value, the code may be set.

The EVAP, or Evaporative Emission Control System, prevents fuel vapors from escaping into the atmosphere in all cars. This is a crucial procedure since both regulators and automakers aim to reduce vehicle emissions and enhance fuel economy.

The EVAP system frequently sends diagnostic data to the Powertrain Control Module (PCM or in certain vehicles ECM) when the computer runs various checks on EVAP systems and operations. Any potential problems with the EVAP system generate different DTCs, which are relayed to the dashboard by the PCM.

Code P0496 is defined as “Evaporative Emission System High Purge Flow.” Purge flow is the last step of the process in which fuel vapors leave the charcoal canister and enter the engine to be burned. Code P0496 will be triggered if an unintended vacuum arises in the system, and the “Check Engine” indicator will illuminate on the dashboard.

Which Models Are Affected By The P0496 Code

MakeAffected By P0496 Code

What Are The Possible Causes of the P0496 Code?

The EVAP system is very complicated, and a multitude of parts, components, and connections may result in the P0496 trouble code. These are, in our experience, the most possible causes of the P0496 trouble code:

  • Defective EVAP Purge Volume Control Valve ( this is the most common cause)
  • Defective EVAP or fuel pressure sensor
  • EVAP system hose is leaking
  • Electrical connections are poor
  • Faulty vent solenoid
  • The leaking from the charcoal canister

With some cars, additional causes may be at play. In Hyundai vehicles, the cause may be a leaking EVAP system hold, whereas, in Kia and Mazda vehicles, the cause may be a defective purge flow sensor.

What Are The Common Symptoms of The P0496 Code?

Code P0496 symptoms are usually difficult to detect. Although EVAP is a closed system, it is impossible to detect or hear purge flow abnormalities such as these by ear. But, there are a few symptoms that your vehicle may be experiencing problems with the P0496 code:

  • The check engine light: As there is no evident symptom that is specific to the P0496 code, a blinking check engine light is the most obvious indication of its presence.
  • Vehicle starting trouble: The accumulation of vapors in the engine chamber may prevent the vehicle from starting. Yet, this one can be deceiving, since there are numerous other reasons why the vehicle may not be starting.
  • The engine is running rich: Another difficult-to-identify symptom that can potentially cause long-term engine damage.

Is It Safe To Drive With a P0496 Code?

Yes, it is safe to drive your vehicle with the P0496 trouble code. But, although you can safely drive with this code, it is essential to solve this problem as soon as possible.

Difficulties starting the vehicle may be annoying, but they will not have lasting effects on the vehicle or its engine.

In contrast, if your car’s engine is running rich, you may be causing major damage to the engine and may incur a hefty repair price in the future. In addition, the mileage you obtain per tank of gas will be drastically reduced.

How To Diagnose The P0496 Code

Here is how to diagnose the P0496 trouble code:

  1. Use an OBD-II scanner to verify the P0496 code’s presence.
  2. Gather and evaluate the freeze frame data to determine the source of the issue. Clear any trouble codes and perform a test drive.
  3. If the trouble code remains, examine the fuel cap. Verify that it is neither damaged nor leaking, both of which are simple to repair.
  4. Examine the volume control valve for purge. It may become stuck open. With the engine off, disconnect the hose from the fuel tank to the purge volume control valve. Also, you must disconnect the connector linked to the valve.
  5. Start the vehicle and use a vacuum gauge to determine what is emanating from the valve where the hose was removed. If there is a vacuum, you know the valve is leaking and must replace it. During this test, another engine code may be set, but you can delete and disregard it.
  6. Check for leaks in the EVAP system. Compress the venting tube leading to the control valve. The system is then pressurized with a smoke machine. If smoke is emanating from the seals or hoses, the leaks must be repaired.
  7. If there are no leaks, you must inspect the electrical wiring. The multimeter will assist you in examining the EVAP sensor wire. When the pressure sensor is removed from the car’s charcoal canister, the voltage should change. Your service handbook will outline the appropriate voltage. If it is not functioning properly, the EVAP pressure sensor may need to be replaced.

It is always possible that these steps will not lead to the correct resolution. If so, you may need to have a specialist examine it.

Most Common Mistakes When Diagnosing The P0496 Code

Here are the most common mistakes when diagnosing the P0496 trouble code:

  • Not examining all components of the evaporative emission system correctly.
  • Before examining the system for leaks, the purge control valve is replaced.
  • Before evaluating the electrical connections and wiring, the EVAP pressure sensor or purge control valve is replaced

How Much Does It Cost To Repair P0496 Code?

One or more of the following fixes may be required to resolve the underlying cause of the P0496 trouble code. The estimated cost of each prospective repair includes both the cost of essential parts and the cost of labor.

  • EVAP Purge Volume Control Valve replacement: $150-$200
  • EVAP pressure sensor replacement: $125-$350
  • Repair the leaking from the EVAP system: $150-$750
  • Repair the poor electrical connections: $50-$1000
  • Charcoal canister replacement: $125-$650
MakeP0496 CodeRepair Cost
ToyotaYes$50 – $1000
NissanYes$50 – $1000
ChevroletYes$50 – $1000
BMWYes$50 – $1000
AudiYes$50 – $1000
BuickYes$50 – $1000
MercedesYes$50 – $1000
GMCYes$50 – $1000
SuzukiYes$50 – $1000
TataYes$50 – $1000
LexusYes$50 – $1000
MazdaYes$50 – $1000
MitsubishiYes$50 – $1000
KiaYes$50 – $1000
JeepYes$50 – $1000
FiatYes$50 – $1000
HondaYes$50 – $1000
HyundaiYes$50 – $1000
OpelYes$50 – $1000
FordYes$50 – $1000
FiatYes$50 – $1000
PeugeotYes$50 – $1000

What Repairs Can Fix The P0496 Code?

Repairs that can fix the P0496 trouble code are:

  • Replace the EVAP purge volume control valve
  • Check and replace the fuel cap
  • Replace the EVAP pressure sensor
  • Repair the leaking from the EVAP system
  • Repair the poor electrical connections
  • Replace the charcoal canister

How To Fix The P0496 Code

Below are some steps that you should take to fix the P0496 trouble code:

  • Use the scan tool to determine the code.
  • Reset the code and drive the vehicle to determine whether it returns.
  • Check the fuel cap and if necessary replace it.
  • Replace the defective EVAP purge volume control valve.
  • Repair or replace the EVAP pressure sensor.
  • Repairing leaks from the EVAP system hose.
  • Check the vent solenoid, and if it is faulty replace them.
  • Repair the poor electrical connections.
  • Replace the charcoal canister.

In Conclusion

Fixing the P0496 trouble code is another example of preventing minor issues from becoming major ones. The longer the problem persists, the more likely it is that a costly and time-consuming repair will be necessary.

If your check engine light is illuminated but you are unable to establish the cause, you should immediately have your car inspected by a professional. You may find a quick and inexpensive solution that saves you money on costly repairs in the future.



Vide Polowenski, Senior Mechanic

The information in this article is current and up-to-date in accordance with the latest mechanic SOPs.

Please take the time to leave a comment if this article has helped you in any way, you need additional help, or you have a suggestion.

Latest Posts

  • Crankshaft Position Sensor Lifespan

    Crankshaft Position Sensor Lifespan

    Crankshaft Position Sensor (CPS), is a pivotal component in your vehicle’s engine. Often referred to as the engine’s heartbeat monitor, the CPS plays a crucial role in ensuring optimal engine performance and efficiency. In this blog post, we delve into the intricacies of the Crankshaft Position Sensor’s lifespan, exploring the factors that influence its durability…

    Read more

  • Crankshaft Position Sensor Fuse Location

    Crankshaft Position Sensor Fuse Location

    This tiny component plays a significant role in the smooth operation of your vehicle’s engine, influencing everything from ignition timing to fuel efficiency. In this post, we delve into the often-overlooked but crucial aspect of vehicle maintenance and repair – locating and understanding the crankshaft position sensor fuse. The crankshaft position sensor fuse in cars…

    Read more

  • How to Replace Your Crankshaft Position Sensor

    How to Replace Your Crankshaft Position Sensor

    Replacing a crankshaft position sensor might seem like a daunting task, reserved only for seasoned mechanics, but with the right guidance, it can be an achievable challenge for even the most novice of car enthusiasts. This crucial component, often hidden within the intricate labyrinth of your engine, plays a pivotal role in the smooth operation…

    Read more