Q: Code P0456

asked by on September 19, 2016

Evaporative Emissions System - Small leak detected. As you know this vehicle has no gas cap. I tried to clean the filler flap, clear code but it returned again.You have any ides Thanks John

My car has 42122 miles.
My car has an automatic transmission.

Hi, thanks for writing in. I’d be happy to help.

The P0456 code is for a small leak and the only way to find such a small leak is to have the system pressurized using the test port under the hood. The system is pumped full of a smoke that has a special dye in it that will show up with an ultraviolet light. Once the leak is detected then you can repair it as needed. The fuel fill valve and the purge valve under the hood is the two main areas that leak the most. This test will isolate the leaks for you and should be done before replacing any parts.

If you would like help, consider having an expert automotive technician from YourMechanic come to your home or office to inspect and diagnose this issue for you, and make any repairs as needed.

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

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

How do I use the engine block heater in a 2012 Dodge Ram?

The engine block heater helps heat up your engine during very cold weather. If your vehicle has the engine block heater, you should always use it when starting your car in extremely cold conditions. Here’s how. Locate the engine...

My coolant is boiling out of my overflow tank.

This is most likely the result of a failing fan switch relay or a failed thermostat. The thermostat is a component that regulates the flow of coolant through the motor based upon specific temperatures. When the engine reaches a certain...

How do I flash the high beams?

You can flash the high beams to get someone’s attention, or to alert other drivers. To do so pull the turn signal lever towards you, and then release it. The high beams will flash on and then off, and the...

Related articles

2012 Subaru Outback vs. 2012 Chevrolet Impala: Which One Should I Buy?
When you compare a 4-door sedan versus a 4-door wagon, there are going to be some obvious differences. Even though the Outback looks car-like, the ride, the handling, and the mileage are going to make it more similar to an...
A Buyer’s Guide to the 2012 Honda Insight
The The 2012 Honda Insight is a dedicated hybrid five-door hatchback. Designed for those who want an environmentally conscious vehicle that also saves considerably at the pump, this hybrid also features a lower price tag, even for a fully equipped...
A Buyer’s Guide to the 2012 Cadillac CTS
The The 2012 Cadillac CTS comes with high tech features and a large amount of standard equipment when compared to its Japanese and European counterparts. The CTS is available in wagon, coupe, and sedan models to fit the needs of...