Normally most people would reset the error code and ignore it and see if it comes back.
If it came back then you'd either do a compression test or take it to a magic fixing place.
However, there are some weird people out there who want to take the engine out and get messy.
So, The Question Is...
Well, luckily, as all smart engines are in-line, it's easy to answer.
The cylinders are always numbered from the end with the pulleys, chain and belts.
And here's a picture with its top off. See the chain on the right.
So, now you know, go get dirty and take your engine apart. Weirdo.