[rk1021]

Hi,

I have a 2014 bmw x3 xdrive28i. I recently got a check engine light. The obd scanner said it's " P0456 : EVAP System Leak Detected (very small leak)". I searched online and found that a dirty old gas cap could be the issue.

I checked the cap. It was pretty dirty with soil under it. I cleaned it up nicely and put the cap back. After some time the check engine light went out. I scanned with OBD2 again. But, I still see the same error code. I have deriven the car for over a week now. Possibly around 150 miles.

Has anyone else faced this issue? Does the code go out automatically or do I need to get it checked/fixed?

Thanks in advance!

[Hellshalfacre]

Originally Posted by rk1021

Hi,

I have a 2014 bmw x3 xdrive28i. I recently got a check engine light. The obd scanner said it's " P0456 : EVAP System Leak Detected (very small leak)". I searched online and found that a dirty old gas cap could be the issue.

I checked the cap. It was pretty dirty with soil under it. I cleaned it up nicely and put the cap back. After some time the check engine light went out. I scanned with OBD2 again. But, I still see the same error code. I have deriven the car for over a week now. Possibly around 150 miles.

Has anyone else faced this issue? Does the code go out automatically or do I need to get it checked/fixed?

Thanks in advance!

Hello. There is a service bulletin for this issue for certain years relating to the leak detection pump module pressure switch ("NVDL" located right above the passenger side rear wheel.) But a small evap leak could be anywhere from the purge valve and associated hoses to the filler neck seal, to the canister, to the hpfp seal in the tank. The system works by pressurizing the evap system and measuring pressure drop. The code/CEL can be constant or intermittent.

The way that a shop will diagnose this code will be to use a smoke machine to find leaks in the evap system, or to replace the NVDL according to the service bulletin. If you Google your year and the associated code, the details of the bulletin will pop up from a number of sources. Good luck to you.