Hello everyone,

I was getting a P1456 error and a check engine light eventually coming on. After getting under the car and looking at the area in question, I couldn't see anything wrong with vacuum canister, the vacuum lines, and the CVS valve plugged into the vacuum canister checked out ok. However, I did smell fuel vapor, so I opened the plastic around the 2 way check valve, the smell was strong from there. I touched it and could see there was a little bit of fuel that might be leaking from it. Replacing that 2 way check valve was the issue. I drove almost 200 miles on it over the day and the error is now gone. Before, it would show up shortly after a second drive from resetting the errors in the computer.

For some reason, in my head, I always thought the check valve was the item plugged into the vacuum canister, I now see it the is the item next to the canister and that it has two sensor plugs into it.

Just thought I would share.

I followed these instructions for looking at and testing :
https://static.nhtsa.gov/odi/tsbs/20...53545-3978.pdf

Page 9 shows the diagram withe the location of the 2 way check valve.