Im currently getting a "loose gas cap" warning and engine light is on, but gas cap is tight. Anyone know what this could be?

Vehicle has 60k miles and its out of warranty. Hoping this is something small.

 

Probably the valve on the vapor recovery canister is failing. The system creates a vacuum on start to test the evaporative recovery system integrity. If it doesn't hold, you will get a message like you are now receiving. Time to go to service.

 

Thx! Service booked for tomorrow.

 

Just following up on this since getting same issue, replaced gas cap but to no effect.

will obviously be following up on the vapor canister as HBerman said.


But also curious What ended up being the issue according to the dealer?

 

I had the same issue. I will check my service invoice when I get back to Chicago on Wednesday and let you know what it said.

 

thanks dude.

 

I took the car to Mercedes Manhattan. Here are the notes from the invoice. This work resolved the issue. Total invoice was 2114.19 but also included replacing the front USB port.

K** AFTER DIAG, FOUND CHARCOAL CAN W/ DIAG MODULE AND PURGE
IMPLAUSIBLE, RECOMMEND; REPLACE CHARCOAL CAN AND BANK 2 PURGE.
MISC DIAG AND REPLCED,,,,CHECKED VEHICLE, FOUND CHECK ENGINE MIL ILLUMINATED, CONNECTED

,,,,BATTERY CHARGER, CONNECTED SDS, PERFORMED SHORT TEST, FOUND CODE#
,,,,P04427A A fine leak in the evaporative emission control system was
,,,,detected. Leakage or a defective seal was
,,,,detected., PERFORMED SYSTEM LEAK TEST AND SMOKE TEST, REPAIR
,,,,ESTIMATE PROVIDED AND ON OTHER LINE. PROCEEDED GUIDED TEST, PERFORMED
,,,,FUEL SYSTEM LEAK TEST, LEAK TEST PASSED OK, PROCEEDED AND CHECKED FOR
,,,,CONTROL UNIT SW, NO NEWER FOUND, PERFORMED TEST OF PURGE SYSTEM, AFTER
,,,,ALL TEST FOUND DIAG MODULE IMPLAUSIBLE VALUES, REMOVED RIGHT REAR
,,,,WHEEL, REMOVED CHARCOAL CANISTER W/ DIAG MODULE, , CHECKED MODULE,
,,,,FOUND MODULE HAVING INTERNAL ELECTRICAL FAULT, REMOVED CANISTER,
,,,,REPLACED CHARCOAL CANISTER W/ DIAG MODULE, RE-INSTALLED REMOVED
,,,,COMPONENTS, CLEARED FAULT MEMORY, CHECKED AFTER REPAIR(ok)/RUN TIME ON
,,,,LINE B /

 

Thanks man, ordered the purge valves as they’re pretty accessible, relatively cheap, and currently noisy AF…

i am at 92k so this doesn’t seem out of the ordinary.

I’ll do test procedures if it doesn’t solve the issue.

 

Did you replace the ones behind the head lights or the one in the wheel well?

Any one can point me to the part numbers?

I am getting the loose gas cap error

I also got a bunch of others about stability control and differential, my guess was it was from the new tires being over inflated but that went away, or else my batter is on the way out? Would be strange for these to all act up simultanously?

Thanks you

 

at least trickle charge your battery all the way up and see what happens (Case example)

purge valve part numbers (Sticky):

https://mbworld.org/forums/w213-amg/...ml#post9203757

https://mbworld.org/forums/w213-amg/...ise-fixed.html

https://mbworld.org/forums/w213-amg/...ml#post9203739

 

Thanks! I didn't realize the ones behind the headlight could throw the loose gas cap error, I assumed it was the charcoal cannister

I do get the common ticking noise, any way to confirm if it's this purge valve or the charcoal cannister?

Thanks very much

 

most likely this is your canister like the c63 guys also experienced - I'll keep an eye out for a part number

edit:

 

I wonder would the failure of the charcoal canister seal come under the federal emissions warranty?

 

makes sense but no one has exercised that angle yet ... I like the idea

 

Anyone any idea how to go about it?

does it have to be main dealer? I was going to get my car fixed at an independent

I don’t want to bring it to the dealer just for them to tell me to pound sand on the warranty

 

no idea - my best guess is to pull emissions warranty documentation on the vehicle and look at the criteria - if anything hooks, walk in with a smile, a dozen donuts and that documentation to your local dealer service center

 

Just to update this, it was a failing fuel pump in the end as well as the purge valves that were throwing the codes. $1400 later and my check engine light is gone and the car is more responsive with full fuel pressure

 

win-win-lose

(performance is back - no CEL - $1400 gone)

 

I had this same exact problem (CEL, sometimes the gas cap warning (I replaced the cap and seal first thing))... the car would shudder sometimes like it was in limp mode until I restarted it. The dealer was throwing out all kinds of issues. My Indie guy on Long Island fixed it in ten minutes by replacing the purge valves.

It is caused by topping your tank off beyond when the gas station pump shuts off. Essentially we are pushing gas back into the valve and over time they fail. $160 in parts and labor.

Here is a pic of the parts. (2018 E63S Wagon with 55K mileage)

 

Well, other than wasting gas, it seems like it does more damage than expected by topping off.

 

I'm an idiot, and have always had the bad habit of trying to get as much fuel into the car as possible at every fill-up. My purge valves went bad in another car around 4 years ago, and I still have to remind myself to stop being an idiot at the gas station. Tat last 4 ounces really isn't going to help, but it definitly can and does cause damage. Great PSA

 

So WTF?!

Just to treat the Wagon, I decided to purchase an AMG gas cap. Prior to swapping out the original cap for the AMG one, I had NO codes, NO CEL and NO "loose gas cap" warnings. Now I'm getting intermittent loose gas cap warnings, and just today a CEL. I checked the gas cap for tightness, shut the car of for 15 minutes and still have the CEL. How is it that just swapping out my gas cap can lead to these issues? I have since put the original non-AMG cap back on in the hopes that all returns to normal(?).

I need a sanity check.....🤦🏻‍♂️

Mike

 

there were some defective ones, deep breath:

https://mbworld.org/forums/c63-c63s-...ap-messag.html

https://mbworld.org/forums/w213-amg/...ap-issues.html

 

FML

That would be just my luck.

I disconnected the negative battery terminal for 15 minutes and even with the non-AMG cap back on; still have the CEL.

This is so asinine.

 

it'll clear - drive a bit or use a scanner to clear it