My gas gauge wont register - 2007 Mercedes-Benz C230 Sedan

if gas gauge dont work and vechicle wont start fuel pump faulty but check fuel pump fuse or relay first make sure they okay.

Your sending unit in the tank is bad and needs to be replaced. There is a short in it. That is the only thing that can go wrong with it. There is probley a broken wire on it so it wont read right.

I would say that the gauge valve inside the gas tank is faulty. either that or the gauge itself

Hi,
Check both the gas float and the fuel gauge. The terminal wire on the fuel float when grounded on the bare metal body of your car it will register on your gauge as "FULL ", if not the fuel gauge is malfunctioning and have to replace. When it register to your gauge as "FULL", the problem would be the gas float inside the fuel tank.
A technician could replace it for you.
Hope that helps you out.
Thanks for asking FixYa!

could be sending unit in gas tank or loose wire on back of gauge or gauge

Wont take gas and the gas gauge stays full? This question really doesn't make sense. But if you cant put anymore gas in the car and the gauge says full then you have a full tank of gas. If the gauge always says full even when the gas tank is not full then the sender unit is failing or the gauge itself.

Your fuel sending unit is probably a little sticky...
I wouldnt worry about it... It's the bottom half of the tank of gas that matters , right?

Did you check to make sur you have voltage at the sensor? Before you changed out the sensor did you run a wire from one post to the other post on the connector?
doing this will make your gas gauge go to full,unless the gauge is defective

The gauge circuit is shunted on most cars, this is wierd, but needed to stabilize the readings... Your description sounds like normal function. Drivers would complain if the qauge were to be instant, going around corners, starting, stopping, all move fuel, and the gauge would indicate this, cauing driver alarm...Been this way for ever, although yours sounds like it is on the far side of the scale...if it reads correctly after a while, you could replace everything and you would have the same performance.

hi gumy

sound like a sticking float in your gas tank,this small float is what registers how much gas is in the tank