"Check Filler Cap" mystery solved...

[MrFixIt]

Since I've completed a bunch of work on the engine three weeks ago, I have been getting the CFCap message almost every time I start the X. The message would stay on for only a few seconds, and it might repeat a few times if I don't reset the gas cap (new). The X runs great and was not effected by CFC message.

Today the SES P0455 Evap Large Leak showed up. I thought for sure it was a bad (new) gas cap, but confirmed it wasn't the gas cap.

Spent hours searching and reading this site today. What caught my attention was the "Fuel Tank Breather Valve" located at the front of the engine on the driver's side.

I had to remove this unit when I did the upper timing chain gasket. To make a long story short, I thought the C-clamp hose was on tight and all the way in--it wasn't (smacking myself).

I gently pulled on the c-clamp to check it. The hose came right off as if it wasn't attached to the valve.

That sumbi*ch was so hard to get on properly. Had to press the c-clamp so hard my thumb is still sore. It took 20 minutes of grunting to hear that magical click...it's properly installed. (I must have had a brain fart when did it last month)

What I learned today is that the SES fault code P0455 and "Check Filler Cap" messages are not always about the gas cap like it is written on the gas cap.

Erased the fault code, started up the X, and no more CFC messages. So far no CFC after 7 starts and shut downs. All is good.

Thanks Xoutpost!

[motordavid]

Good detective work, good fix, good pic, & good post!

[swissfrank]

great find!

[imola38]

Nice job MrFixit! I see your in Fla. What area? I'm in St. Simons island about 40 mins from Jacksonville. Not alot of BMW enthusiasts around here.

-Ben

[faz]

I love these posts. Thanks for sharing the info, and the pic, and ....

[MrFixIt]

Originally Posted by imola38

Nice job MrFixit! I see your in Fla. What area? I'm in St. Simons island about 40 mins from Jacksonville. Not alot of BMW enthusiasts around here.

-Ben

I'm in South Tampa near MacDill AFB.

[Purplecty]

Did the error come back after properly connecting the hose to the vent valve? I am experiencing the same issue after replacing my vent valve with a URO one. I guess I need to go and make sure I connected that hose properly...

[Purplecty]

After reseating my vent valve hose, the check filler cap message did not appear for 4 or 5 starts and then this AM I got it again. Is the x5 cap suppose to click when tightened? Also I noticed mine appears to be genuine but has a blue gasket ring around it. Aren't these normally green?

[TriX5]

Simple test, check with a voltmeter what ohm reading you get on the valve itself when you pull off the wire. After I put the V8 back in the car last fall, this error came up (as it did before pulling the engine). INPA showed it as a loss of continuity on the valve's internal circuit which was easily confirmed by checking it with a volt meter. Purchased a new unit and the problem was fixed. Lately I have seen a number of people reporting this issue and there are many on offer on the internet which seems to say this is a common maintenance item.

[Purplecty]

I replaced the valve with a NEW URO part (cheap $40) and it passed the tank vent test successfully with DiS. Before replacing the valve I would get a tank vent system error but now I get that and a leak error after the replacement...