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Discussion Starter · #1 ·
I bought the 2022 sienna xle in November 2021.
When full my fuel tank 16 gallons its show 560 miles to drive .
Last month I took my car to Toyota dealership for 5000 miles maintenance after that I am getting only 500 miles when tank is full.
Are the dealership manipulate the computer system.
Where should I complain.
 

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2016 Toyota Sienna LE FWD
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Dealers are not able to manipulate your Distance to Empty.

That Number mostly always changes, the one in my third gen changes quite often. There are multiple variables on what can affect that number such as on how you drive, the type of fuel such as summer and winter blends.
 
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I think the Distance-to-Empty mainly depends on (1) How much fuel the gauge senses in the tank, and (2) Your history of fuel consumption. Have you done anything recently that may have increased your fuel consumption? Like driving very fast, or hauling stuff on the roof at high speed, or towing?

The 500 miles-to-empty (given that the tank is 18 gallons) translates into 28 mpg, which is very low. The 2022 Sienna shows 32.4 mpg average on Fuelly, and the summer figures are typically better than winter.
 
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Fun fact: Air density leads to fairly significant MPG changes for highway driving.

Drag force is linearly proportional to air density. Air density changes 10% from 40 °F to 90 °F. All else being equal, this means that at 40 °F your air drag is 10% higher than when you’re driving at 90 °F. Exact proportions of air drag to other losses vary from vehicle to vehicle, but some searching showed that at highways speeds maybe 75% of vehicle energy is used to counter to air drag. If this is so, then if you got 35 MPG highway driving at 90 °F, then the same speed highway driving at 40 °F with the same gas would give you a MPG of 32.4. Humidity also changes air density, but going from 1% RH to 99% RH at 90 °F changes air density by 1.8%, so humidity plays a much smaller role in air drag changes than does temperature.

The air density causing drag to vary therefore is likely the biggest single factor by far of any MPG changes that are not related to changes in driving habits, and the numbers I quote here do line up with real world experience I saw with my non-hybrid Sienna used for primarily highway driving during the drastic temp swings I experienced this spring. My driving was identical so I started researching this because I noted my fuel economy varying drastically by temp, which could not be explained by summer vs winter fuel blends, since it didn’t seem the energy content of the gas would change that much. Nor was it possible that the gas was switching back and forth from summer to winter blends multiple times exactly in sync with the weather. If anything they will change blends twice a year, once in spring, once in fall.

Not saying this is what the OP saw, unless they live in the Southern Hemisphere and experienced a winter cold snap. More likely, as mentioned, driving patterns changed, using more fuel, so the car adjusted the estimated mileage to match the new fuel usage. If so, the longer mileage estimates will return when the driving usage returns to previous levels.
 
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