Why Prius Fuel Gauge Reading Incorrectly: How to Fix an Inaccurate Fuel Gauge

Last updated on January 13th, 2023 at 08:32 pm

If your car fuel gauge is not reading correctly or not just working totally,  there are a couple of actions you take to fix or do proper fuel gauge troubleshooting but first, you need to be able to identify what each reading stands for is so you can know when the fuel gauge is reading incorrectly. YOU may love to read this on how do you know if your car ac is overcharged

first a car fuel gauge are simply a machine designed to display pointers to help you understand that state in which your fuel quantity is. For instance, if the pointer on your fuel gauge is at “E” it means that your tank is empty and when it points to “F” it means that your car tank is full.

And then there are other indicating lines and marks to also help you gauge where and how much fuel is remaining within the tank of your vehicles.

However, there are some cases where this fuel gauge does not seem to be working probably due to one problem or the other, in that case, you need to know why the fuel gauge is reading incorrectly so you don’t run out of gas at a bad spot.  

That is the reason I like to share with you some of the reasons for fuel gauge reading incorrectly precisely we are going to look at reasons for Prius fuel gauge reading incorrectly. Some Related articles you may want to read too are: Why Prius Won’t Turn Off & How to Turn It Off and this on 3 Ways To Know How Much Gas You Have if Fuel Gauge is Broken

 Then we will discuss how do you reset the fuel gauge on a 2009 Prius, 2010 Prius fuel gauge calibration and what to do if you 2008 Prius fuel gauge flashing light on the dashboard, What to do when the fuel gauge reads empty when full, and finally how to check how much gas you have with a broken fuel gauge if you just have not yet had time take your car to a dealership for your fuel gauge to be properly diagnosed and fixed.

So first let’s look at what fuel gauge reading incorrectly does not mean,

Related Article:

What Fuel Gauge Reading Incorrectly Does not Mean

 An inaccurate fuel reading does not mean that you have a problem with your car engine and its functionality nor does will cause any serious issues to your car. so

The fact is you can totally drive your vehicle very well without risking damaging any major component of the car. However, if you are not able to read the correct gas quantity in your car will mean you running out of or low on gas without any warning or notification.  

This can be very frustrating if it happens in a location where there is no gas station.  The main role of a fuel gauge is to show the quantity or the amount of you fuel your tank and to tell you when there is a need to refill your gas tank.

What will Wrong Fuel Gauge Read to My Car?

 The thing is driving your car with an incorrect fuel gauge reading will directly cause any harm to your vehicle, however indirectly it could cause long-term problems such as a clogged fuel pump, engine overheats, and premature wearing of other engine components and parts, etc.

This happens simply due to the fact that with the incorrect fuel gauge reading you will normally not know when your fuel level is low and requires a refill and as such, driving your car long at a low fuel level is what causes the clog and other engine issues you are likely to experience.

This is why you really need to plan to refuel when your gauge reads low as quickly as possible which bad reading will not you know or do.

With that in mind, let’s look at the general reasons fuel gauge reads incorrectly before focusing on Prius incorrect fuel gauge reading.

General Reasons For Fuel Gauge Reading Incorrectly : fuel gauge not reading correctly

There are 4 main reasons why the fuel gauge is reading wrong and can be stuck on full and they are i) failure of the gauge sending unit, ii) circuit problem, iii) gas gauge failure and, iv) a non-operational instrument cluster.

1. Failure of Gauge Sending Unit

 One common cause of the fuel gauge not working issue is the sending unit failure of the fuel gauge. So what happens is that the fuel gauge might read the voltage feedback but can’t display the correct info at the time because the sender is bad which usually is what shows the signal “F” meaning Full or “E” meaning Empty.

Here the sending unit moves on a continuous motion and rubs on other variable resistors while you are driving your vehicle. 

The failure of the gauge sending unit is caused due to the constant friction which wears off the contact point.

2. Circuit Problem

Lost connections on the fuel pump module and Corrosion could be the reason for the circuit problem and could also be the reason why your fuel gauge is stuck on full.

Depending on the main cause of the problem for instants with a voltage issue from the fuel sender making the gauge not to receive any voltage feedback, this might disrupt the entire gauge circuit.

The interruption and inconsistent ground from either the car gauge or the fuel sender unit causes issues that linger even when the sender starts working fine.  

3. Gas Gauge Failure

This is a less common one for a car fuel gauge to be reading incorrectly but yet not outright impossible reason. This occurs when the car internal gauge circuit is shorted, defective, or open.

4. Non- Operational Instrument Cluster

The last and least common reason for the fuel gauge not working situation is the non-functional instrument cluster. Funny this is the least scenario or cause but it has the most expensive repair cost and that is because our modern cars have a full integrated circuit unit which means that when one part goes bad, the entire unit automatically requires replacement. As such, making this issue, one of the most costly ones to fix.

Causes of Fuel Gauges and Fuel Gauge Sending Units To Failure

  • Blown or damaged fuse
  • Damaged gauge
  • Stuck gauge sending lever
  • Disconnected circuit wires
  • Broken wires
  • False grounds
  • Broken or failed fuel gauge sending unit

Reasons for Prius Fuel Gauge Reading Incorrectly & 2010 Prius Fuel Gauge Calibration

Well, the simple truth is causes listed above are also the reason for Prius fuel gauge reading incorrectly So in summary I will say that major causes of incorrect fuel gauge reading of Toyota Prius are failure of the gauge sending unit, a non-operational instrument cluster, circuit problem and gas gauge failure.

You read how this occurs above.  And for the 2010 Prius fuel gauge calibration please watch this video here or follow the instruction below.

fuel gauge not reading correctly

How do you calibrate a Prius fuel gauge?   2010 prius fuel gauge calibration

First, calibrate the Prius fuel gauge, you need to start off by turning off the ignition switch. Then you have to press it down and hold on to the “ODO / TRIP” control button as you try to switch on the ignition switch to on position.

Make to hold the ODO knob for 2 seconds, then release and push the ODO button for additional 3 times in 5 seconds, It should look like this: “Release-Press-Release-Press-Release-Press and Hold”.

How Do You Reset The Fuel Gauge on a 2009 Prius &other Models (2004 to Date)

Here is the Reset Procedure to follow if you are trying anywhere from 2000 to 2009 Prius fuel gauge reset this even applies to more recent models up until 2015. This step is also how to fix an inaccurate fuel gauge process

                Prius fuel gauge reset (how to fix an inaccurate fuel gauge)        

  1. Start by parking the  vehicle on a smooth or a level surface.
  2. Then you have to turn on the ignition switch. Put the button on the“On” point.
  3. Now put the odometer display to “ODO” mode and turn off the vehicles ignition knob.
  4. Push & hold the “ODO/TRIP” switch while trying to turn the ignition switch to the “On” point. The ODO button should be held for 2 to 3 seconds.
  5. Now release while you then continuously press the ODO switch for 3 more times in five sec: this will look like this Release-Press-Release-Press-Release-Press& then hold. You have to keep holding the ODO button  up to five seconds until the car leveling info comes up or is presented on odometer board.
  6. Release the switch /button totally at this point.
  7. Then give a moment and now depress and hold  “ODO/TRIP” knob till the odometer display confirms that reset has started (the odometer should reads “1”).
  8. When the reset is fully completed, the odometer will returns to normal.
  9. Then release the button and turn off your ignition.

If this does not work the first time, try it again and again because sometimes it may require multiple attempts for it to work even for experienced technicians. You have to start afresh if you miss a step.

Why is my fuel gauge stuck on full

When a fuel gauge is stuck on full only there 2 possible cause,  one is due a faulty or bad fuel gauge which prevent the resistor from sending voltage feedback to the gauge receiver and display unit and the second reason could be due to a wiring problem from the fuel circuit unit which causes a shortened signal.

How to check how much gas you have with a broken fuel gauge

If your fuel gauge is broken and you want to know the level of fuel in the car to pay constant attention to the dashboard till the fuel gauge shows a red light indicating the tank is empty and you are probably driving on reserve.

In most cases, even with a broken fuel gauge this red will always come up and from then on you have to do a mental calculation of de distances you were able to cover and how much gas you used with should be remaining in your tank.

I hope this article on the reasons for the Prius fuel gauge reading incorrectly was helpful? Please bookmark it for future reference.

Related Article:

Sharing is caring!

Scroll to Top