Odometer and fuel gauge not accurate

Just got a 2001 golf tdi recently. When I bought it the original owner mentioned that when you fill up it is full but only says 3/4 tank but stays there for a long time and he’s ran out of diesel before on a quarter tank so it needs to be filled by quarter tank to be safe. When I did fill up it had been just how he said it. On 3/4 tank after 14 gallons I put in. When I was around the half mark I decided to fill it up to see where it was. So 7 gallons but I did a calculation to see where the average mpg was and it said it put 963 miles within that 7.1 gallons used. This is definitely not right. I did not get 135mpg.
I ordered a scangauge and cable for vag-com but it hasn’t came in yet. The search function hasn’t helped so I’m wondering if anyone is familiar with this and if there is some kind of calibration or something I can do to fix this.

Get to the tank from under the right side rear seat. Remove the sender. Gently clean the wiper area that the float rubs on. Clean this up, check for debris in the tank, clean as necessary.


You may need to recalibrate the fuel gauge, and you'll need your VCDS for that. Do some searches for cleaning the tank sender or fuel gauge sender, and you might even find some photos.


Good luck,


PH