My check engine light went off today I checked with my sct x3 it said P0456 something about emmisions leak ? What does it mean how do u fix it ?

 

Check your gas cap

 

P0456 - Evaporative Emission System Leak Detected (Very Small Leak)
Description: The powertrain control module (PCM) monitors the complete evaporative emission (EVAP)
control system for the presence of a very small fuel vapor leak. The system failure occurs
when a fuel vapor leak from an opening as small as 0.508 mm (0.020 inch) is detected by
the EVAP running loss monitor test.
Possible
Causes:

Very small holes or cuts in the fuel vapor hoses/tubes

Loose fuel vapor hose/tube connections to the EVAP system components

EVAP system component seals leaking. See the Possible Causes for DTC P0442
Diagnostic
Aids:
Check for a missing fuel filler cap or the integrity of the cap.
Check for loose or damaged vapor hoses. Visually inspect the EVAP canister inlet port, CV
solenoid filter, and canister vent hose assembly for contamination or debris.
Application Key On Engine Off Key On Engine Running Continuous Memory
All — — GO to Pinpoint Test HX .

 

So it has to do with the fuel system cause my car has been wasting alot of gas lately.

 

Yeah, like goldenpony said, check to make sure your gas cap is good. If that's good, I would check the hoses.

 

I Google it and found this;

http://www.obd-codes.com/p0456

 

i checked the gas cap it looks good.

 

what would happen if it is left alone and nothing done ?

 

If the gas cap was indeed left loose, it will take a while (a couple of days perhaps) for the light to reset. Make sure the cap is tight and wait a few days and see what happens.

 

My car has this same problem. I put on a new gas cap and reset the computer and still get the codes. For the time being I have just learned to live with it but plan on getting the car on some ramps when the weather turns nicer to see if I can't spot the problem.