I replaced my gas cap and the small emission leak code still came up.
Any ideas?

 

The problem is not the cap.

Post the error code. Likely the code points to something in the fuel vapor recovery/venting system.

Or take the car to qualified shop for expert/professional diagnosis and repair. Chances are whatever is the matter is nothing something you can fix on your own and not something that will correct itself.

Sincerely,

Macster.

 

The code says:

P0456
Fuel tank ventilation system (minor leak) (Below Limit)

Any ideas?

 

Did you try to clear/erase the code? I think it may take several starts with a secure cap for it to reset on its own. Failing that, I would agree with Macster's recommendation.

 

Are you clearing the code? KS-CS has a good point. The code may take time to clear on its own even if the new cap is the fix.

If your car has been sitting idle for a while...I recently came across a Cayman that had been sitting unused for a while and it was in with obvious mice damage.

But along with the obvious damage: carpets chewed up; seats, etc,; there was a gas tank vent system leak error code (I do not recall the code number).

What had happened is the mice had been at the tank vent line.

The tank vent line runs down the center tunnel of the car. The tank vent line is attached to the top of one of the coolant lines, and the tech showed me (he had of course removed the underbody panels) where a mouse had gnawed on the plastic line just to the point a small hole/leak was created. The mouse probably stopped when it tasted/smelled gasoline.

Sincerely,

Macster.