So My C230 Hatchback gas gauge all of a sudden does not read correctly. The odometer is still correct but the gauge is super far off. When the tank is empty the gauge is only just under half a tank. Is there any way to reset the gauge or something? I have been just using the odometer as a gas gauge and refilling it when I hit 300mi.

 

The gauge is controlled by a floating sensor attached to the fuel pump. Wondering if the one in your car is somehow malfunctioning.

 

What work was done before the issue? Pump replaced? Rear sam replaced? There is no calibration that can be done on cluster

 

There are 2 fuel level sending units in the saddle tank. Left and right. The computer uses input from both to calculate fuel volume. You need a scan tool that can show you which of the two sending units is malfunctioning.