you said b/c of CEL light. when did it come on recently or long standing issue? true. if you trigger a true cap-only CEL error b/c of open or non-correctly-closed-cap within 3 cycles it should correct itself. if you're longer than that, look deeper in the forum cap might not be the problem but just another recognizable symptom in a larger issue. experts will/might advise on your further comments have a 55 but a 500 sure does sound fun

 

CEL came on about two weeks ago, no other symptoms that I notice at this point. I went to auto zone and they said "small evap leak" and told me that most times this code means a faulty gas cap. They didn't give me a code number, just "small evap leak". So, I figured it was worth a try to buy a new cap....but as I said before, I can't get the old one off (the strap part) without breaking the strap and if I do that, I will also be unable to attach the new strap.

I am prepared to dig further into this if the new cap doesn't do the trick. Thanks for your advice and the 500 is fun...love it.

 

To answer my own problem....I finally discovered that the strap simply pulls off (ok, prys off with a screwdriver) and the new strap, attached to the new gas cap, snaps into place.

Also, this fix did not resolve my check engine light : (

 

Lisa, do you have a scanner to read the CEL code? now that you know that cap isn't the true issue.

 

I just purchased a scanner and now I have to teach myself how to use it! I will repost when that happens and I find the code. Thanks!

 

My Check Engine Light went off! It took quite a while once I replaced the fuel cap, almost a month, but it is gone!:thumbsup:

 

Lisa, the gas cap may have been the root cause of your problem. By design, the CEL doesn't go out right after you put a new gas cap; instead, the CEL will go out after several (not sure how many specifically) successful on-off cycles of engine.

After replacing the gas cap, you could've RESET the CEL with the use of OBD-II code reader/eraser (I think you just bought one).

 

Darn, I never thought to reset it.... I am still learning lol.

I get great pleasure out of having solved that problem with a $30 gas cap, especially since the parts guy at the dealership gave me a look like I was wasting my money trying it.

I really appreciate this forum and all the help people are willing to give.

I am sure I will be back....my baby turned over 100,000 miles now!

 

Hi Lisa,
I bought a new gas cap because the one I have did not have a strap. I can't find anything to attach the strap loop to. Can you help me?

 

This is a photo of a Mercedes with the filler door on the opposite side of the vehicle but it is the same none the less.

Look for a small nipple, as shown in the photo, where the tether attaches to. If it is missing or broken you must get a new one.

 

Hi,

The strap has to be snapped on a nipple on the right of the filler pipe, just underneath the filler cap takes place when plugged.
It might be broken on your's, that would be the reason your current cap don't have a strap.

 

My 2005 W163 ML's Fuel cap tether attachment point is located just underneath, and to the side of the fuel filler pipe located on the Left, forward of the vehicle, at approximately the 10 o'clock position. It is underneath the fuel filler cap which must be removed to see the attachment point.

It appears from the above descriptions of location that there are several locations depending the year.

Mike

 

I'm not sure the problem is the cap. The ML has a unique fuel cap "failure." mode - the "low fuel" light would start to flash if you have a cap error (I believe that's the indicator). I don't know this is for all years (why not?), but that's the indication on my 05. I believe the attachment looks like the picture 43sqd posted (Post #11 ). On my 05, the strap is a bit deeper in the pocket of the cap - not on the cap frame as shown in the pic. Probably more difficult to access, but it does not look like the attachment has anything to do with the inside of the wall. I have attached two pics of mine below - sorry, don't know why pics are not loading.

 

Hi,
"The ML has a unique fuel cap "failure." mode - the "low fuel" light would start to flash if you have a cap error (I believe that's the indicator)"
Another common failure is the cap gasket which get worn and light the CEL with P0442 code (evap, small leak).

 

Thanks for pointing that out. The flashing may then be for "no fuel cap" - massive pressure differential.

 

My 05 ML500 fuel cap attachment point looks nothing like Darkman's 05 ML500 in post #14 or 43sqd's post #10 above. Strange

Mike

 

Hi,

Yes, should be that with P0441 code (evap, major leak)

 

I get the rapid flash low fuel light after driving 10 mins. Swapped caps with my 05 Chrysler. No change at first. Saw flash during a few trips. But have not seen any flashes in the past few trips.

Just to be sure, I ordered a new cap.

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Hope this helps.