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P2418 OBD-II Trouble Code: EVAP Switching Valve Control Circuit/Open

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P2418 trouble code definition

A P2418 trouble code is related to a vehicle’s evaporative emissions control system, or EVAP. These are fitted to most modern vehicles to help trap gasoline vapors before they escape into the atmosphere, either from the fuel tank or the fuel system. The system is often controlled by a switching valve or purge control solenoid.

What the P2418 code means

P2418 is an OBD-II generic powertrain code for a voltage problem with the EVAP system and its switching control mechanism. The EVAP sends variations of pressure and flow as degrees of voltage to the engine computer. If any of those are off the manufacturer’s parameters, a Check Engine Light will be triggered.

What causes the P2418 code?

While the main cause for a P2418 will typically be the EVAP switching valve or solenoid, EVAP systems are made up of numerous little components. Likely causes include:

  • Faulty EVAP switch valve or control solenoid
  • Loose gas cap
  • Faulty purge control solenoid
  • Damaged or clogged charcoal canister
  • Vacuum leak or damaged hoses
  • Bad fuel pressure or flow sensor

What are the symptoms of the P2418 code?

It’s rare for an EVAP code to cause any noticeable symptoms. However, it isn’t uncommon for a P2418 to be accompanied by other EVAP codes.

How does a mechanic diagnose the P2418 code?

First, a mechanic will usually clear the code and test drive the vehicle to see if the P2418 immediately returns. If it doesn’t, the problem is intermittent and may require longer periods of driving for the cause to become more apparent. Other simple fixes may be tightening the gas cap.

However, if the code persists, a serious of tests will help reveal if the switching valve or control solenoid are to blame. A professional OBD-II scanner may be able to activate a part of the EVAP system called the leak detection pump. If this isn’t working in first place, you could spend hours chasing a problem that doesn’t exist. After confirming that this pump works, the mechanic can move on to testing the switching valve by applying voltage to the solenoid. This should trigger it off and on – if not then the valve will need to be replaced. If it is in working order however, chances are there will be other EVAP codes that will help your mechanic determine what the route of the cause is.

Common mistakes when diagnosing the P2418 code

Forgetting to check the leak detection pump can cause a lot of lost time and wasted repairs to get rid of a P2418. This should be checked to ensure it is working properly. A lot of EVAP codes are also triggered due to loose gas caps and vacuum leaks.

How serious is the P2418 code?

A P2418 will not cause any damage to your vehicle nor will it affect its performance in any way. It will however cause your EVAP system to not work according to the manufacturer’s specifications and as a result, your vehicle will emit more emissions that normal.

What repairs can fix the P2418 code?

The most common repairs for a P2418 are as follows:

  • Visual inspection of the EVAP system, including the gas cap, coupled with clearing the code to see if it returns
  • Replacing the switching valve or control solenoid
  • Replacing broken vacuum lines
  • Replacing a damaged or defective charcoal canister

Additional comments for consideration regarding the P2418 code

EVAP codes can be some of the most frustrating trouble codes to fix and troubleshoot. They can also be some of the easiest due to the high probability of a loose gas cap being the cause. It’s important to try the easiest repair route first before diving in to buying replacement parts.

Need help with a P2418 code?

YourMechanic offers certified mobile mechanics who will come to your home or office to diagnose and repair your vehicle. Get a quote and book an appointment online or speak to a service advisor at 1-800-701-6230.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
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