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Hey am new here really need your help on this after so many attempts my 2017 GlC 300 Mercedes car has a full tank of gas but fuel gauge and range is empty. Theres no check engine light . The fuel does light up when I start the vehicle but went back to off Any help would be appreciated! I think someone had this issue before but I cannot find back the post on how to solve it I drink no issue but I have being using mental fuel gauge as I really don’t know what’s the issue
What’s the best scanner should I get for it?
I bring it to a car mechanic and he said he use the computer scanner and show me a list of possible caus
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Last edited by KingWeston; Jun 30, 2025 at 06:56 AM.
2014 ML63, 2018 GLC43, 1929 DB victory six sports roadster
Autel are good scanners, get one that suits your budget. It could be something as simple as a plug or wire broken or disconnected. Your mechanic has just given you a list of parts they can throw at it.
Did this happen after re fueling or something else.
It happen on a rainy day when I was driving home looking at the gas tank to determine the amount of gas was in the tank I stop the car turn it off and turn it on back the lights come on, on the fuel gauge then went back off and from ever since I have that issue when I start it the car gauge light come on and then when to show the amount in the tank it goes off with no light even when I put full tank with the tank running over
I check some fuses not sure if I check the right fuses that related to the fuel gauge because am not sure which fuses operate the fuel gauge I use my multimeter by taking out some of the fuses and test if it makes a beep sound on the meter that’s all and once I hear the beep sound I put it back assume it’s good so am not sure which fuses operate I see a electrical drawing with fuses and location in the back of a fuse box I look through by name If I see anything about fuel gauge or fuel sensor just seeing like odermeter doors lights etc
I check the fuse box in the truck the one beside the battery and the one at the driver side beside the steering wheel but I will test them again once more to make sure. Cause I remember few days before the incident of the gauge I did use my car to jump start a next car because his car battery died so am wondering if it could impact the fuses after
You might try pulling the fuel gauge fuse or disconnecting the battery and see if that resets it. Best not to jump start cars due to all the electronics in these cars, unless you have the correct jumper leads or better still a jump start pack.
I check some fuses not sure if I check the right fuses that related to the fuel gauge because am not sure which fuses operate the fuel gauge I use my multimeter by taking out some of the fuses and test if it makes a beep sound on the meter that’s all and once I hear the beep sound I put it back assume it’s good so am not sure which fuses operate I see a electrical drawing with fuses and location in the back of a fuse box I look through by name If I see anything about fuel gauge or fuel sensor just seeing like odermeter doors lights etc
You can test all of the fuses while they're in the fuse box by touching the open spots that are visible "in situ" with the probes. The blades that insert into the fuse box are directly connected to the little open metal spots on the surface of the fuse that's visible while the fuse is still inserted.
All you're doing is checking continuity from one side of the fuse to the other.
Ok great I will look at the diagram to see which specific fuse is for the fuel gauge instead of going through all of them and I won’t jump start again I did a big mistake
You can test all of the fuses while they're pouring the fuse box touching the open spots that are visible "in situ" with the probes.
All you're doing is checking continuity from one side of the fuse to the other.
I don’t really understand what you explain here is it possible to explain in simpler terms are you saying I should keep the car on and test the fuses that s for the fuel gauge
oh ok I see I will try that again before I took them out one by one but I will do it this way and see if they all work that means possible issue with the fuel sensor in the tank I am assuming
Thanks. I couldn't find a good picture.
That way you can test all the fuses in short order.
I check all of them not too long ago and they all make connectivity sound on the meter but I will go at it again to make sure I left none untested I just do a ran through but tomorrow I will go at again for sure thanks
So this happened to my 2017 glc as well. The dealer replaced the fuel pump. That fixed it
oooh so basically it’s the pump because I went to a mechanic yesterday to do a diagnostic he told me there’s no readings from both the sensor so he is saying basically seams it’s the pump or the pump cover needs to change so I guess am going to have to get a new pump
If you can start the engine, your fuel pump is working fine. If you're fuel gauge looks bad, then fuel sender issue.
Fuel sender is like a toilet float and sends the different resistance to ECU by the float angle. The plate resisters or the copper contacts worn out then wrong resistance to the ECU, and wrong fuel display happens.
If you can buy only the fuel sender, it's cheaper.
Don't just buy only the small pump itself without the housing which doesn't include new sender.
If you can start the engine, your fuel pump is working fine. If you're fuel gauge looks bad, then fuel sender issue.
Fuel sender is like a toilet float and sends the different resistance to ECU by the float angle. The plate resisters or the copper contacts worn out then wrong resistance to the ECU, and wrong fuel display happens.
If you can buy only the fuel sender, it's cheaper.
Don't just buy only the small pump itself without the housing which doesn't include new sender.
ooh ok I see
I pull it myself took out the pump which I tested it not sure if am doing the right testing way so I bring it to the mechanic he put a scanner on the car he saying there’s no readings coming from both sending unit which he may be thinking it could possibly be the pump cap that the fuel the both fuel sending unit plug into I don’t know
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