vikingdiesel

Ever since I got the drivers side valve cover gasket replaced, I'll get the GAS CAP OFF message almost once a day until I restart the car. Went back to the dealer and the vacuum hose by the driver's side valve cover was off, so they reconnected the hose and the next day, same error message. Went back to the dealer and they did a smoke test, turns out I had a major leak on the shut off valve on top of the charcoal canister. Got the valve replaced, picked the car from the dealer and ten minutes later, STILL the same message. Anyone have any suggestions on what is causing this?

cij911

Since the message happened after you did the valve cover gasket, have you checked the vacuum lines coming off the valve covers (feeding into the TB) ?

MindBend

Yep...there's one at the rear/bottom of the TB (has a coupler) that is really easy to come uncoupled there if you take the driver's side air box off, you can get to it.

vikingdiesel

Any pics of this vacuum line, make sure it's the same one

MindBend

Take the air box off and you'll see it connected to the back of the valve cover (it's black...about 1/2 diameter). It then goes up and back to the bottom of the throttle body.

Gadget

I had my vacuum line come off when I pressure washed my engine. Follow that vacuum line forward to the area of the head light. There is a control valve there. That is where mine came disconnected. Check that out.

G

vikingdiesel

Do you have a pic of that line? So it goes from the back of the valve cover to the drivers side headlight area?

Max.H

I thought when you get the gas cap light is because you have fuel vapor leaking due to fuel sender leak?

AMG X

^ not necessarily, you could double check visually or pull up the codes with STAR. It could be the vent valve, charcoal canister, the vacuum line mentioned above, or even the gas cap itself (bad seal). Basically, all of the emission control parts for fuel vapors

Gadget

Here is where that vacuum line connects up by the driver's headlight. You can see that round thing that is a vacuum switching valve to apply suction to the EVAP recovery system. It is the thing with the wire connector on it supported in the rubber mount.

vikingdiesel

Thanks for the pics but apparently that's not my problem. Dealer called and said I have a vapor leak from the fuel pump sender assembly. Part #2114705194. Is that pretty much a complete fuel pump with the sending unit and filter? Do these cars have one or two pumps in the tank?

Gadget

You can pop up the cushion of the back seat. Under that you will see the two covers. When you take them off you can see the two access points for the fuel tank. On the passenger side (USDM) is where the two fuel pumps are. On the driver's side is where the filter is and the outlet hose.

G

vikingdiesel

So the part number that the dealer wants to replace is on the drivers side, is that common issue?

vikingdiesel

Anyone? I want to make sure that this can actually cause the problem I'm having before I continue dumping money

BoostedAero

So, I had this issue pop up today

Did your dealer's final diagnosis resolve the issue?
(fuel pump sender assembly. Part #2114705194.)

Also and lastly, was this (or will this be covered by the fuel tank settlement)

2008 pumps and assembly were repaced at the dealer, then the tank was replaced by the dealer in CLT while under my care in June. So I am wondering related to work also?

Max.H

In for more info on this. This seems good to know.