Fuel Warning Light

Blisteringblue · July 4, 2014

Just noticed when sorting out my receipts this week. I filled up with 10 miles showing on the range this week, with the warning light coming on around 50 miles to go.

It only took 57 litres to fill it back up. So by my basic maths skills there was still 13% of the tank full when I did this with 10 miles on the range !!

Why do they do this? Is it so you don't run to the dregs of the tank? I thought that was an old wives tale from the old days :eerrrmm:

rayaans · July 4, 2014

Its similiar with my RX450h. Except the fuel low warning is written on the screen between the speedo in place of the cruising range.

I think it only calculates cruising range based on fuel outside the reserve range. When you get "fuel low" it means fuel is going to go into reserve.

In mathematical terms, its basically a systematic error that the programmers have included to make sure you dont run out of fuel as it makes you think you're going to run out much sooner than you actually will.

Steve44 · July 4, 2014

And so commences the "how far can you drive when the range goes to zero" game. Or the "is it possible to get the tank Max or more in the tank".

On my current car, I've had the needle off the bottom of the gauge and still couldn't get the declared tank Max size back in! I know when the range/refuel now message is displayed I've got about another 30 odd miles left before it becomes really squeaky bum time!

DJP · July 5, 2014

And so commences the "how far can you drive when the range goes to zero" game. Or the "is it possible to get the tank Max or more in the tank".

On my current car, I've had the needle off the bottom of the gauge and still couldn't get the declared tank Max size back in! I know when the range/refuel now message is displayed I've got about another 30 odd miles left before it becomes really squeaky bum time!

Spot on! Although I believe it's a game played mainly by us males. My wife cannot understand why I am not heading for the nearest Shell (air miles collector) garage as soon as the tank is approaching 1/4 full, never mind when the range shows --.

Sent from my iPad using Lexus OC

Clearline · July 5, 2014

By total accident and a closed petrol station I usually use, I ended up actually ran out of petrol in the IS300H. The computer readout was perfect. I was literally less than a 1 mins drive from the next petrol station which I drive to on the Battery!

DJP · July 5, 2014

By total accident and a closed petrol station I usually use, I ended up actually ran out of petrol in the IS300H. The computer readout was perfect. I was literally less than a 1 mins drive from the next petrol station which I drive to on the battery!

That was very handy! How many miles do you think you drove with the range showing zero?

Sent from my Iphone using Lexus OC

Blisteringblue · July 6, 2014

Wow, Battery to the rescue. I'm about 150 miles from home with computer telling me 138 in tank so will give it a go.

Blisteringblue · July 6, 2014

Lol bottled it at 1 mile and filled up! 57 litres again. Feel like such a wimp ;-)

Steve44 · October 13, 2014

Re visited this as I ran the tank down the other day, having to stretch it to a petrol station. At 0 range it displays Refuel Now on the display permanently and I got the fuel gauge, which slowly turns red as it ebbs away, to completely disappear.

I ran probably 20mile past the range 0........

.....Still could only get 58ltrs in the tank, so still had 40 odd miles left in car!

Blisteringblue · October 14, 2014

I've probably gone 30 miles past now too, and still plenty in there. I'm into the habit of filling up on zero but I guess there is still a good 75 miles in the tank from there if you really want to chance it.

michaelH · October 29, 2014

I read a warning on this forum that running out of petrol in a lexus hybrid would be a bit of a disaster - and not one that could be fixed by an AA or RAC patrolman with a can of unleaded. Instead it would be a transporter trip to a dealership for resetting the hybrid system. But perhaps only if you try to keep going when the system calls for petrol?

Logan, are you sure you ran out of fuel just when the fuel gauge said you would? What happened to show that you had run out? Are you sure it had not been showing 0 for a few miles already? I have had four lexuses, and all of them had 'over-cautious' fuel gauges. My experience with the IS300H is that it says '0' and 'refuel now' when there must still be about 6 or 7 litres (enough for 50 miles or more) remaining in the tank, and that seems to be the experience of most contributors here.

dochybrid · October 31, 2014

I had the fuel light came on at 42 miles cruising range. I continued driving for 10 miles after the cruising range got reset..

So overall one tank gave 620 miles with 50.3 mpg and only 10 miles extra range after the cruising range touched zero..I felt the car would stop at any point, was close to a gas station, phew!!!;)

michaelH · November 1, 2014

Ah, but when you refilled, how much did you put into the tank before it was full? If as I suspect it was around 60 litres then you still had another 5 or 6 litres (or 45-50 miles range) at the bottom of the tank. At 50.3 mpg [actual brim to brim measurement ] your range on a full tank should be in excess of 700 miles.

But of course you were absolutely right to refuel when you did.

dochybrid · November 1, 2014

You are right..filled the tank with 59 litres....

Guess I perceived car's usual sluggishness in the Eco mode to be the final bit before it had stopped completely....

mpls · January 31, 2017

Interesting topic, I usually fill up before warning lights come on.

Today my low fuel warning light came on and I drove another 11 miles or so miles before I pulled into a BP station and filled up, it only took 54.3 litres.

Is that normal, the display showed that i had around 22 miles left showing.. ?

I

capese21 · February 1, 2017

Old thread revival.

I doubt the hybrid system would allow electric only if out of petrol. The engine & the motor work together. Anyone ever tried it?

NemesisUK · February 1, 2017

23 minutes ago, capese21 said:

Old thread revival.

I doubt the hybrid system would allow electric only if out of petrol. The engine & the motor work together. Anyone ever tried it?

It states in the handbook...

"Running out of fuel
When the vehicle has run out of fuel and the hybrid system cannot be started, refuel the
vehicle with at least enough gasoline to make the low fuel level warning light (→P. 523)
go off. If there is only a small amount of fuel, the hybrid system may not be able to start.
(The standard amount of fuel is about 10 L [2.7 gal., 2.2 Imp. gal.] when the vehicle is on a
level surface. This value may vary when the vehicle is on a slope. Add extra fuel when the
vehicle is inclined.)"

DanD · February 1, 2017

You also have to consider that the bottoms of tanks are rarely completely flat because they are molded to fit in with whatever is around them. This means that you end up with some petrol left in some part of the tank that remains inaccessible no matter what.