I have a 2004 E 320 Wagon, and on two occasions it has run out of fuel, with the gauge saying I still had 1/4 tank of gas. I have brought it to the dealership twice, once after each occasion. The first time, they said the fault was caused by a wrong version of a program on the computer. The second time, they said they took out the gas tank, and checked the sensors inside, and all was working as designed by the manufacturer. (Does Mercedes really intend for the fuel gauge to read incorrectly????)

I have noticed the problem happens when the tank is first filled, then as the fuel us used, it seems to get "stuck" at 1/4 tank.

The service (or lack thereof) was done at Bill Ussery, in Coral Gables, FL.

Any suggestions? Thanks in advance for your help.

 

The software change were most probably to alter the reading towards being on the safe side. So it doesn't look as though it is an incorrect calibration of the system.

However I wonder how the dealership satisfied themselves that the tank unit was working OK.
I suspect they checked to see if the extreme positions of movement correlated with empty and full but did they look to see whether the float (or whatever the exact mechanism is) could get stuck at 1/4 full due to some mechanical problem. Rough edge, binding etc.
However if the tank unit is some fancy electronic capacitive sensor (which changes state when washed with fuel) I guess my suggestion won't help.
Good luck.
Stuart

 

Thanks for the reply. I am supposed to talk to the service manager and I want to have as much information/ammunition as possible when talking to him. I am not happy that after two occurences, they come back with "could not replicate."

The service tech told me they could not replicate the problem - I pointed out that the milage on the car was only 11 mile difference from when I brought it in, to when the gave it back - hardly enough to go from above 1/4 tank to empty.

If anyone else has some additional ideas, they are greatly appreciated!