My manual says the fuel light will come on when about 2.8 gallons of fuel remain. But on the display that shows range approximation I'm getting a totally different reading when the fuel light appears.

For example, by the time the fuel light comes on, my range approximation is usually estimated on the display as 30 or fewer miles. But according to the manual, when the fuel light comes on I should have about 2.8 gallons remaining, or a fuel approximation of about 75 since the car is averaging about 27 mpg.

When I fill up shortly after the fuel light comes on, I'm only able to squeeze in about 15 to 15.5 gallons (18.5 gal capacity) . . . so obviously the fuel light is more accurate than the range approximation, but the 2 aren't reading similar to one another. The vehicles I've had prior to this '12 es350 all had similar readings amongst b/t the range approximation and the fuel light. Not spot on, of course, but very similar.

Is this something I should get looked at or not worry about it?

 

I typically do not go by that light, once I hit 1/4 tank on the fuel gauge, I just head to the gas station. It's best to be a little proactive in that aspect, you never know what might happen and you end up running out of gas on side of the road.

 

It is not a good idea to wait till the light comes on to fill up. By doing this, you may overheat the fuel pump. As the fuel pump only cools by the gas which is in the tank, and if you let the gas level drop to low it may not cool the pump.

 

The range is also pretty conservative...

 

mine is totally inaccurate; eg today i filled up after the light was on for a few days of light driving. The range left said 6km; the fillup took 58.5 L out of 70l capacity!!! So I has at least 100km+ of driving left.
I luv hightech

 

So it appears that Toyota/Lexus is trying to protect the fuel pump by have the range approximation show me running out of fuel way before I might actually run out.

 

More like they're trying to protect you from running out of fuel in general.

 

I've also noticed a huge disparity in the miles I can drive on the first half of the fuel gauge (about 300)versus the second half of the fuel gauge (about 150) down to almost empty! I conclude the fuel gauge is very inaccurate - so don't rely on it for something like running out of gas.

 

Ha, true. I was used to my last 3 vehicles having a fuel warning light that acted in a very accurate fashion with the range approximation display, so this car has thrown me for a loop in how vastly different they estimate fuel.

 

I've never paid much attention to this feature but will have to check out my car to see how accurate it is or isn't.

When I get to 1/4 tank or so, I fill it up. If I'm caught by surprise and the low fuel light comes on, it's usually yikes and I stop for gas.

 

I hear you, LexBob2, but when I fuel up after the fuel light comes on, I can only squeeze 15-15.5 G in my car (capacity is 18.5). What about you? How much fuel can you put in when the fuel light comes on? Other than the possibility of a fuel pump overheating (mentioned above, which from this point forward I will begin paying attention to!), I didn't get concerned when the fuel light came on b/c I figured I still had 3-3.5 G remaining.

One time I drove until the fuel approximation display said "2", as in 2 miles approximate range remaining. At that point the fuel light had been on since about 26 miles range remained on the display. I fueled up at that point. I was only able to get about 15.6 gallons in the tank, meaning I still had approximately 2.9 gallons remaining.

Like I said, not a big deal. Just have never owned a car where the fuel light and approximate range display differed so much. Good conversation and thanks for everyone's input so far.

 

I actually drove my es for about 10 miles when the approximate range was 0 miles remaining. I always thought that the fuel approximation is based on the mpg you drive on the last fill up, so if you drive differently, your fuel approximation will not be accurate.

 

The approximation is based on a global fuel economy that you don't have access to. Thats why when you take a long highway trip, the range will increase on fuel-up and will gradually sink back down while your driving is mixed/city.

If you unhook the battery and let it reset, it will go back to the factory spec.

 

good or bad I let mine go all the way down quite a bit. I can tell you without a doubt the gallons left is about 2-3 gallons when the miles to empty is at -0-. So basically you have about 40-60 miles rem when it reaches zero. I can put at most 16 gals when i refill around -0-, Most I've at zero was about 15-20 miles past on trip back from Chicago and got caught in between towns where your not sure whether to get off exit or not. That episode believe it held about 17-17.5 .
Anyway not that i suggest doing like me...you can be assured you have couple gals when it reaches zero. The Lexus serv advisor confirmed this to be true.

 

This is true. Lexus goes out of its way to make sure you don't run out of gas. I find this built-in inaccuracy to be frustrating and stupid. How about giving me guages that are accurate, with no buffers, so I know how much gas I have left instead of having to guess?

It's like a clock manufacturer making its clocks five minutes fast so you're never late. Just give me the truth and let me work it out from there.

The old wive's tale about low gas levels hurting the fuel pump doesn't apply to modern cars. They're designed to operate with low levels of fuel and it does the fuel pump no harm.