Distance to Empty - Not even close
 

Hi all,

Will bring this up @ 5k service with Lexus.

With ~1,900 miles on it we have consistently found the Distance to Empty short by at least 100 miles of remaining range. Filled up last night and it said 25 miles of range left. The RX took 11.6 gallons and was full.

I understand the full 17.2 gallons may not be fully usable, but flagging 25 mile range with 5+ gallons of fuel remaining isn’t helpful.

Previous fill ups have all been around 12-ish gallons with the DTE showing less than 20 miles of remaining range.

Do your RX 350/500’s behave the same?

Anyone brought it up with Lexus Service Department?

Thx.

Yes my 500h acts the same. Always Fills up below 50miles to empty. Couldnt get the gas tank filled up above 12 gallons. Now my previous Rav4 has this problem and Toyota recalled our Rav4 for the gas tank. Maybe the the RX has the same gas tank as the Rav4?! Did that fix the problem? No, problem was still there. Ive always mention this to the service people but they always answer 'it all depends on the driving behavior etc' Is it a big deal for me? No, but I do hope Toyota is aware and hope to see what they come up with this time.

Do you think it is just Lexus being safe as it hybrid and based on driving habits a lot can change?

In my current RX 2019, tank is 19.8 and with meter reading zero I still have about 4 gallons reserve left and this has always been case with Lexus at zero on gauge 4-3 gallons left, most ever been able to put in is about 15 gallons ever. Really thinking the math is adding up that this is design as even with 2004 rx it was same at zero gauge always had 4-3 gallon reserve as well.

Thanks for the replies. I’m going to chalk it up to intentional (aka a design feature).

Might I ask what does the fuel gauge indicate when the range indicates 25 miles left? :uh: Does it indicate empty as well??

Yes, only the very bottom segment of the fuel gauge is illuminated.

An update.

At 12 miles DTE it alerts on the center display that only 12 miles are remaining.

Before the alert the DTE counted down 1 mile for every mile traveled.

After the alert the DTE count down slowed dramatically which was unexpected. I didn’t reset a trip odometer because I didn’t expect the change in behavior. My estimate is it took another ~25 miles to get DTE to 0. Next time I’ll reset a trip odometer at the alert.

So, after much more driving that I planned I got DTE to 0.

After zero I continued driving and the DTE range of 0 was replaced by ‘Refuel’.

I then filled completely at Costco with 13.4 gallons. So, almost 4 gallons of tank capacity remaining @ zero range left. Extremely conservative.
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Thats wild...4 gallon reserve.

Is it possible the 500H has a smaller tank becuase of the extra electric motor back there? Maybe it has a 15 gallon tank?

4 Gallons reserve seems wildly too much.

I wouldn't think the gas tanks would be different sizes, or it would say in the specs.\
Ya, a bit much at 4 gal.

Here is the comparison specification sheet. Fuel capacity is 17.17 gallons (65 liters) - the same as the 350h
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Lexus has always been that way, on my 2019 RX it holds 19.8 gallons and at 0 I can at most push just little over 15 gallons into it. Even on prior models going back 2000s has always been that way.
I also have Audi and that thing is very accurate with maybe a gallon to spare if even that at 0.

Not al Lexus models are that way - My 2018 LC500 indicates 0 miles remaining when it's down to about 1.5 gallons left of its 21.7 gallon tank - quite accurate I'd say. :D

Man this is really bad. I filled up again today from 10 miles left in the "tank" and it only took 12.4 gallons.

This is crazy. Why does lexus leave 5 gallons of fuel reserve. If they even let me have 4 of those gallons, that 100 more miles.

Like I dont want 125 miles of fuel reserve when the car is telling me to "refuel now" thats abusrd

Agree. It appears to me they took the approach of 50 miles of normal reserve and then added another 75 on top of that as you drive.

I’ve been hand calculating my miles per gallon and the RX mpg calculation is accurate.

Here is from my last tank.

Filled tank - Distance to Empty says ~400 miles. Hand calc says it should say 17 x 26 = 442 miles. 42 miles in reserve, OK, i can live with that.

Drive - Trip odometer = 333 miles, DTE = 0. Hmmm, where did the 67 miles go (for 400 initial estimate)?

Refilled tank with 12.5 gallons leaves 4.7 gallons. 4.7 gallons x 26mpg = 122 miles range should be left.

So the DTE calculation seems to start with ~50 miles of buffer and then adds another 75 miles to the buffer on top when you drive.

So, curious, do the rest of your RX500s hit 0 DTE @ ~330 miles on the tank?

We now have ~2,500 miles and have filled up consistently as the DTE nears 0. The amount of fuel taken is consistent, the mpg is consistent so I don’t think it is misbehaving. I think it’s operating as designed around a poor choice of the DTE design point.

No way Lexus missed this in testing. One my colleagues was part of the US automotive test group at Honda and they track everything.

@Lexus - why? Put this at the top of the list for minor fixes in the next S/W roll.

I have a feeling this is a software bug.

From my last 2 fillups I have also gotten around 330 Miles on the full tank until DTE 0 and required only 12.5 gallons for fill up.

Give me my extra 100 miles of range Lexus.