Hi guys, I have a 2001 Volvo V70 T5. The fuel gauge has been acting weird lately, here is the problem, when I fill up my tank everything's perfect the gauge is at MAX, then it starts dropping normally and at about 200 miles of driving it comes to the halfway mark, which is normal given that this vehicle goes about 400 miles on a full tank. The problem starts when it reaches the halfway point. For example this is what it does every time, for example the other day while I was driving, the gauge went from half full straight to red at once, then knowing I had only driven 200 miles, I knew I had gas, so I kept driving, and once I arrived at my destination, I looked down and the gauge shot back up to half full, it always does this after reaching the halfway mark and sometimes it goes down and stays in the red, I go to refuel and it takes about 16 gallons, a 21.1 gallon tank with a gauge in the red takes 16 gallons, how could it be in the red with 5 gallons of fuel still remaining. Any ideas? Please help, thank you

 

P.S. It did the same thing today, I drove to school, while driving it fell from a little over the halfway mark to just a little over the red, and from being 280 miles to empty, it went to 110 miles to empty, parked the car, went to class, cam back 2 hours later, the gauge was still in the same spot. I drove out of school, stopped at a traffic light, looked at my gauge, and slowly it started rising, rising, rising, and it stopped at the same mark it was at before it fell, a little over halfway, and it read 290 miles to empty tank. ?????

 

One of the 2 sending units are going bad. The most common one is the drivers side.

 

Hey Tech thanks for your help. That's what I was guessing but where are these sending units exactly located, what do they look like, and what are some signs that the sender is bad or is there a way to test them?

 

You would access the sending units from under the rear seats. You can look at what they are doing if you had the proper tool to read them.