Q:Does P0456 clear itself?
A:This code can take quite a while to go away on its own. The car has to run the drive cycles at least twice before the code will clear on it's own. You should have the code cleared, then drive the car to see if it comes back on. It would be the quickest way to determine if the gas cap was actually the problem.
Here, Auteldiag.com recommends you to use a cheap obd2 code reader to erase the fault code.
Take a example：
Problem
There was a yellow check engine light coming on the Dodge RAM 1500 2012, so I wanna use the Autel AutoLink AL619 code reader to find its reason.
Read Codes
Firstly, plug the cable into OBD2 port to connect with Autel AL619, it is underneath the dash on the driver’s side.
Put the key into ignition, turn it to ON position, do not need to start it.
Press “OBDII/EOBD”.
It is showing the MIL status is on which means the check engine light is on. And it did find one code.
OK >> Read codes >> Stored codes
It is showing one P0456 fault code: Evaporative emission system leak detected (very small leak).
Go back to see the “Pending codes” & “Permanent codes”, it is showing the same code. So that’s why caused the check engine light to stay on.
Reason
In the case of an evaporative emissions, evaporating actually just taking the evaporated fuel from the tank & the fuel system. In general, instead of just venting it off into the atmosphere, it draws it back into the engine and then burns off those emissions as opposed to, sending it off into the environment. It is a closed-loop system, so any leaks in that system will cause a check engine light and will not necessarily affect the performance of the vehicle. But it will certainly be a troublesome code that you should deal with.
It is a very small leak, but I had to fix this problem.
Solution
Go to the gas tank filler to rotate the gas cap, it’ll probably fix the problem. I had this problem about 10 thousand kilometers ago, so over time the gasket in the gas cap can start failing. Not per seal is very well and prevents that tight seal from existing. So when you’re filling after a fuel always make sure your gas pump is good and tight. Rotate it for a couple clicks to make it tight.
If this problem goes away and it doesn’t come back for a while. I’m gonna just call it human error, that’s because I didn’t have my gas cap tight enough or at some point I may have to buy another gas cap. You can even see it says”A loose cap may turn on service or check engine light” on the gas cap.
Clear Codes
Now let’s go back to clear the codes, hopefully it doesn’t come back again.
Erase codes >> Yes
Erase done!
Now I‘m gonna turn the key off, and start it up. Alright, no check engine light.
Let’s go back to the Autel AL619, press “OBDII/EOBD” to diagnose again...
Okay, so you can see now, it says 0 codes found, and the MIL status is OFF.
Problem was solved.
This is using Autel AL619 Scan Tool to diagnose & solve check engine light problem for a Dodge RAM 1500 2012.
