Hello everyone I recently changed a bunch of stuff on my e55 (valve covers, black series engine mounts & transmission mount, ball joints & tie rods) I did all of these at the same time so the car was down for a week or so because I took my time and would work on it after work. I finished up today and started the car up, it was smoking a bit but that’s to be expected because a bit of oil gets on the headers. I took it for a drive and it was driving ok but towards the end of the drive the car made a weird sound when I was coming to a stop and braking a little hard. I would describe it but I honestly don’t know how. It was sort of a suck? Or like a light grind. And when I came to a full stop at the red light the gas light started to flash. And the red indicator said “check gas cap” I don’t exactly know how it sounded but it did it once more when I was coming to the next stop at a stop sign. When it did it again I kinda was worried I was gonna ruin something so I stopped braking and just ran the stop signs and got home (don’t worry I was really close to my house). I turned the car off and checked under the intake to see if I left anything unplugged but all was well. I also made sure the gas line I took off for room was snug which was also good. I put the intake back on and started the car again, this time it had a check engine light but the gas light wasn’t flashing. I plugged in my obd scanner and got those codes listed on the title. Does anyone have any suggestion on what it might be I would really appreciate it (I attached a picture of the obd reading below).

Double check the hardpipe next to the throttle body, it should be plugged into a rubber bung you can barely see. Follow that hardline to the driver side headlight. It should be connected to a solenoid there. If all those connections are ok, then it might be the EVAP valve in the back of the car. I believe you have one with a solenoid valve attached to it, I live in the Netherlands and it seems I have a simpler EVAP container.

I created a video for replacing it, that might help you

Like Andy said, check the hardline where it plugs into the supercharger through a rubber grommet. One of the hardline brackets is attached to the valve cover so this line is often pulled loose while pulling the valve covers. Hard to see but it's there under the surge tank. (Following photo is not mine.)

That pipe blows my mind. These engines have almost NOTHING as far as vacuum lines and are really one of the simplest engines as far as that goes. Some of these new cars you need a schematic just to figure out hose routing. With that being said the one and only important vacuum line on this engine and everyone screws it up !! LOL It's all good !!! I did it one time as well so hope it's your issue....easy fix.

I am getting the PO455 "check engine light".

Maybe I'll do a cold smoke check and see if I find anything.

Exactly, I had the same thought. My 2001 Seat Leon 1.8T 20VT (VW Golf MK4 platform) had such an elaborate vacuum system, with a lot of possible failure points. I love the fact that the M113k is so simple, less things that can go bad

Thank you it ended up being this and it was fixed. Unfortunately I took it for a drive and when I brought it home it was knocking. Hopefully it’s not very bad but I’ll probably have to take it to a mechanic.