twenty2

I have a 2002 ML 500 - Has anyone experienced this? If so what could be going on?
When my gas gauge reached it's 1/4 left mark, as usual like any other time, the orange fuel light indicator came on and the overhead display flashed "FUEL". I went to the gas station to fill up the tank, letting the nozzel auto shutoff - indicating that I am full. What I found to be wierd was when I was pulling away from the gas station, I noticed my overhead display was still flashing "FUEL" - which usually resets to display the number of miles I have on the tank. What I also then noticed was that when I got home - which I literally live about 2 miles away from the gas station, by the time I got home, my gas gage showed I was only 3/4 full. Now I know I could not have used 1/4 tank of gas to go 2 miles. When I got home I shut the car off and turned it on again thinking that perhaps that would rest things - that didn't work. I pressed the reset button too - that didn't work. I drove to work this morning which is approx 32 miles from home - I noticed that about 1/2 way to work - my gas gauge was now showing that I had slightly below 1/2 tank left and the overhead display was still flashing "FUEL". Now I know I just filled uplast night! I then noticed that the overhead display finally stopped flashing but now was displaying that I had 618 miles - which is the highest I have ever seen it - it then proceeded to count down from 618 miles one-by-one number until it stopped counting at 193. It stayed right around there with the approximately 15 more miles I needed to go yet to work. It's obvious to me that I may have a sensor problem - but unsure what is happening. I've never experienced this before. Any suggestions? How costly will this be to fix?

C43AMG

It has happened on both of my vehicles.From what I understand Mercedes has "issues" with the contacts on sensors in the fuel tank.From what I've read and been told they corrode and eventually fail.The replacements are supposed to have a different plating on them ( Gold ? ) so that they don't tarnish or corrode as easily. You will probably have to have them replaced.

PaulX608

I have an '01 ML430, and I had the same problem. It's a bit of a job to replace. The fuel sending unit is on the side of the fuel pump assembly, inside the fuel tank. To get to it, you have to remove the back seat, pull back the carpet, and remove the access plate in the floor pan. Once you get to that point, it's not too bad. You disconnect the fuel lines from the pump, unscrew the retaining ring, and remove the pump assembly. The new one goes right in and hooks right up. My dealer wanted $1000 to do it, $550 for parts and 4.5 hours labor @ $100 per hour. I was able to get the parts online for $365 including a new fuel filter, and my 14 year old son and I did the job in about 5 hours. I would rate this job as a 7 out of 10 for DIY difficulty, not that the labor is overly technical, just very tedious.

I've read about a lot of people with this problem, and so far I haven't heard anyone have the problem come back with the newer design unit. I think I posted a thread about this job after I did it, lemme see if I can find it and post a link.

Click here for the other thread

twenty2

Okay - funny thing - it now has been working on this tank of gas. Since posting this message, and about 3 tanks of gas, sometimes it would fix itself and work - tracking the gas properly, sometimes it would malfunction and decide to not to work! I guess this sending unit you all have been referring to is going bad and I should think about having it replaced anyway?

RobertG

relpace it or get a witch doctor to drive out the demons :p

sosh

Its the fuel sending unit whih is combined with the fuel pump. My 02 has never had this issue but my 98 ML did as did the 01 E Class I had. This is an issue with not only MB but with most German cars. I do not believe that the sender/pump is in the tank but located near it. The units were improved some time ago with several changes but there are still occassional failures. Its not a big deal and you still may be under warranty.

ML God

2001-2005 fuel senders dont go bad as much as the older ones. If your saying it is fixing its self then it sounds like you need to have the version coding changed in the instrument cluster. From the factory it is set at normal value. It needs to be changed to "direct sensor value" unless you have an acutal fault code for it. If there is a fault code then the sender will need to be replaced. If there is no code than just change the version coding. your dealer can do that
MLG

PaulX608

Oh, trust me, it's in the tank. Like I said in my thread after I did mine, it's not terribly technical labor. But it is tedious. And his experience with it working again on it's own happened to me too. As soon as I ordered the parts, at a tidy $365 or so, the damn thing started working again and did so for about 4 tanks, then went back to it's previous abhorrent behavior. It's a job, but it can certainly be done if you have the tools, the time, the aptitude, and the patience. Or just pay the $tealership $750 to $1000 to do it.

ML God

I have replaced so many fuel senders that I can have it done in 30-45 minutes tops!!!

twenty2

Hey ML GOD - Where do you live, how much would you charge and when can I bring it over! ha-ha!

Stiggs

Yeah...me too. I'll pay for 30 minutes of labor!!!

ML God

HA HA I shouldnt of open my mouth...even though it take me 30-45 min I still have to charge what ever book time is. Or I can charge you 30 minutes of labor @ $1,000 an hour!! :p

Stiggs

Boooooooo
Hissssssss
Boooooooo

You suck.
Just kidding

twenty2

Just an update - Well it's been weeks since my last post and several tanks of gas and wouldn't you believe it - it appears my gauge is back to normal performing appropriately. The overhead display has kept track of the miles to go and the gas gauge tack has been tracking the level of gas in the tank . . . .hummmmmmmmmmm? I'm not complaining!

PaulX608

It's lulling you into a false sense of security! They do that. Mine stopped and started working a couple times before it died. The funniest was that as soon as I ordered the parts, it started working again! There's an evil being that lives in the tank, and it loves to **** with your head!

Stiggs

Yeah...I find that mine works fine for 3\4 to a little above 1\4 full...then it goes right down to zero when I still have over 1\4 tank left. it goes so far down that the orange light doesn't even come on anymore.