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Hybrid TechnologyUnique topics related to the 2023 up RX model hybrid drivetrain and other features/options found only on the hybrid models. Please use the main forum for discussion about shared components with other fifth generation RX models.
I have an issue with the gas gauge on my new 500h. When I fill the car with gas it shows high 300 miles till empty. But the gauge goes down to where I have on 40 miles left in the tank and the trip odometer says I have travelled only 260 miles. When I fill the tank it takes only 10-11 gallons to fill. The car is supposed to have a 17.2 gallon tank so something is amiss. I took it back to the dealer and they did a software update but that didn't help. I see where others have had the same issue. What is the fix. Anyone else figure out how to correct this problem. Thanks
I disagree with it being an issue. It clearly states in the manual that running the vehicle empty can be problematic for the hybrid system. Which has been referenced several times within that thread. Then you can also argue that running down to empty causes unnecessary wear on the fuel pump. Since fuel also acts as a coolant for the fuel system in vehicles. Folks attempting to overfill their tank and cause issues with their charcoal evaporator will find out soon enough what issues that'll cause.
The facts are, it is also the size tank that Lexus claims it is. Can you get the range if you go be past the reserve point, yes. . I am sure this is a failsafe for those that are not very mechanically/technically inclined. To me it makes perfectly good sense to ensure longevity (reliability) out of a vehicle with Lexus/Toyota. That thread you referenced is almost as comical as the "gas door not flush" thread.
I run my vehicle until what I think is 1/4 empty which I have done in all my vehicles. Never once have I felt the need to go past that because I am not getting the "range" stated. I am able to have my RX500h fill up before the empty light comes on (one bar left on fuel gauge) with 5 gallons/11 litres left. I have yet to drive it until the light comes on, but I am sure that will allow 4 gallons or so left.
As the saying goes "Just because you can, doesn't mean you should".
It's a problem because the reserve is far larger than what Lexus claims it is. If Lexus listed the reserve as 4 gallons, then owners would know what to expect. Lexus claims that, when the Low Fuel warning activates, there is approximately 2.6 gallons or less fuel left. 4 gallons is not approximately 2.6. I've never owned a vehicle that had 4 gallons left when the fuel gauge reads empty.
It's a problem because the reserve is far larger than what Lexus claims it is. If Lexus listed the reserve as 4 gallons, then owners would know what to expect. Lexus claims that, when the Low Fuel warning activates, there is approximately 2.6 gallons or less fuel left. 4 gallons is not approximately 2.6. I've never owned a vehicle that had 4 gallons left when the fuel gauge reads empty
Not sure if you read my post mentioning that I do NOT have the light come on with 11 litres or 2.9 gallons left in my tank. So, it would appear that the reference material you have shared is indeed correct, but your claims in my case are incorrect.
So, not sure what point you are attempting to illustrate here. Because as a fellow owner, it is completely and utterly inline with the manual, Lexus claims, and my own personal experience with this vehicle thus far.
It is unfortunate you do not have the same experience, but your statement of it being a fault implies it is a larger issue. When indeed I doubt it is.
Not sure if you read my post mentioning that I do NOT have the light come on with 11 litres or 2.9 gallons left in my tank. So, it would appear that the reference material you have shared is indeed correct, but your claims in my case are incorrect.
So, not sure what point you are attempting to illustrate here. Because as a fellow owner, it is completely and utterly inline with the manual, Lexus claims, and my own personal experience with this vehicle thus far.
It is unfortunate you do not have the same experience, but your statement of it being a fault implies it is a larger issue. When indeed I doubt it is.
You said you have never driven until the light came on, so i don't know how you can determine how much is left when the light is on.
Yes I have the same problem with our 2024 RX500h. I took it to the dealer and they did a software up date but that didn't work. I see so many other complaints like this but no solution. Come on Lexus get us a fix for this.
I have the same issue. Lexus needs to fix this problem so many have. This is not up to the Lexus standards.
You said you have never driven until the light came on, so i don't know how you can determine how much is left when the light is on.
Not sure if you're having a laugh, but here you go.
The read out on the pump tells you how much you put into the vehicle. When doing the simple math on what the tank holds minus the fill. It's very easy to calculate this.
For example in my case the last fill I put in about 54-55 litres or 14.5 gallons. Tank capacity is 17.2 gallons or 65 litres. If you're getting the rated MPG or l/100km's (and range) then you can figure it out the rest rather easily. I average about 26.5-27.5 MPG.
You're right, I never had the light go on. It is all based on range driven and what you fill vs what is left in the tank, including your MPG. By design I wouldn't be surprised this was done to promote reliability and stop folks from being stranded when the hybrid system has no fuel.
edit: The fuel gauge reading empty is a failsafe. So you go fill the tank! (read my previous post and others referencing). No one is arguing the fuel tank isn't or is empty. This is by design to prevent the hybrid system from not working. Heck, someone even posted a Toyota being run dry and what the impacts are.
Last edited by Measured; Feb 18, 2024 at 07:07 PM.
Reason: added
Ok, I'm confused. You said that "I am able to have my RX500h fill up before the empty light comes on (one bar left on fuel gauge) with 5 gallons/11 litres left. I have yet to drive it until the light comes on, but I am sure that will allow 4 gallons or so left." and now you are saying "For example in my case the last fill I put in about 54-55 litres or 14.5 gallons. Tank capacity is 17.2 gallons or 65 litres. " which would be 2.7 gallons left and in line with the manual.
Regardless, many others have complained here and in other places that the reserve is closer to 4 or 5 gallons, so it sounds like there is a problem, when Lexus is saying that is normal.
Mine is around 3.2 gallons reserve after multiple refills when near "Empty", and the RX450h+ manual states 2.2 gallons.
I have no problem with Lexus saying that larger reserves are necessary. I just want it reflected properly in the manual and consistent.
Ok, then here is my question. If the Prius shows "0" miles to empty with 1-2 gallons left and it is a hybrid, then why does the RX350h need 4-5 gallons? They are both hybrids and made by Toyota. So there shouldn't be any problem running the tank for another 2-3 gallons after the refuel light comes on. You are still not going to come close to running it dry.
I own an Acura TSX with an 18.5 gallon tank rated at 30 mpg highway. I don't even go by the low fuel warning. I just take the mpg shown on the trip meter for the tank and subtract 1.7 mpg as it is always high by this amount, then multiply it by 18.5. So if my actual is 30 mpg times 18.5 equals 555 miles, then I know I can run it approximately 500 miles before refilling. I usually alway fill up between 15.5-16.5 gallons. Never had a problem with the fuel pump not working in 150,000 miles. It's pumping from the bottom of the tank not the middle. Your fuel mileage will also go up the longer you drive on that tank as the car gets lighter. One tank I took it 603 miles before refilling. Had about a gallon left.
I hope to look into picking up an RX350h, but not if you can only go up to 400 miles on a tank. That, and if I can fit in it comfortably at 6'4".
what makes no sense is some claim the system reserves 4-5 gallons for the reserve gas and hybrid system . yet others claim they forced in enough gas pumping slowly to actually get in enough gas to reflect just 2-1/2 gallons left
I usually fill up shortly after the light goes on. Usually I have driven about 425miles and the car takes about 12 gallons. I once drove for a while after the light went on, I had driven 495 miles and the car took 14.5gallons. Lexus says you have 2.6 gallons left after the light goes on. Maybe Lexus uses 2.6 gallons for the reserve and 2.6 gallons to protect and start the hybrid system? I think I read somewhere that if the hybrid engine runs out of gas, you need at least 2.6 gallons on level ground for the engine to start.
Light goes on 12 gallons used, 2.6 gallon reserve, 2.6 gallons to protect and start hybrid. = 17.2 gallons total
What ever the explanation is, I fill up either when the light goes on or shortly before. The 5 gallons left in the tank should protect the fuel pump and I'm fine getting 400 plus miles per tank.
2024 RX500h gas gauge
