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Lexus RX 400h - MPG-Real World Numbers



  • dmbfloridadmbflorida Posts: 38
    I bought a new 2006 400h hybrid over four years ago as did my daughter (both are front wheel drive and this gets better fuel eco than AWD). We live in hot SW Florida so A/C is on most of the time. I get about 26 mpg in city, slightly better on highway. She gets slightly less mpg than I do but she is not as conservative as I am in driving habits plus she frequently leaves the A/C on in the driveway or queue in a 'drive through' place. She has twice the odometer reading compared to me. I traded in a 2004 Prius that I loved but it was not as comfortable or as safe as the Lexus RX 400h which is superior in most features. I personally do not drive a lot and plan to keep my 400h for many years. I recommend this 2006 car highly but I do not know anything about the new models.
  • ronjoronjo Posts: 4
    First post. 2006 rx400h. Bought used w/90k miles. I get about 19mpg, mixed hwy, city. Seems low. Bought new tires - did not change. Tune up-no change. I have 110K miles - do the batteries go bad? - how can you tell? The power meter on the dash seems to go up to 100kWatt if pushed hard. Although I drive like a granny trying to get the best mileage. Highway I can get maybe 23 if I try hard. (My Acura MX 2004 almost gets the same but no hybrid). Otherwise I love it - just hoping for more green.
    (Any good sources for replacement batteries?). Thanks
  • kyxydjkyxydj Posts: 12
    I have 46K on my 2006 RX400h. Currently getting around 30 mpg - I am also driving like a granny to maximize fuel economy. Note: Things like the heater, de-fogger, and air conditioning will make the gas engine come on more frequently. And this makes your MPG go down. Also - when first starting up the RX hybrid, if you have to stop shortly after starting up, like at a light, and the gas engine is still active, slip the car into PARK. Unless it's really cold outside, this will cause the gas engine to shut down while you wait. Do you live in an especially cold climate? I have not seen my MPG deteriorate at all during the first 46,000 miles.
  • something is wrong. it sounds as if you bought an RX300 or 330 (non-hybrid).
    it is possible that the main battery is malfunctioning and this can happen after 100,000 miles or more. I suppose the answer lies in a mechanic checking out the main battery. recently, hybrid main batteries are supposed to be better quality so look for the newest technology if you buy one. sorry I do not know more than this.
    We continue to get about 25 to 26 mpg on our two 400h hybrids but I drive more conservatively than my daughter so my car gets about two mpg better than her's does.
  • mtrsmtrs Posts: 4
    Just to add my Canadian perspective, my real-world fuel economy, in litres per 100 km, has been 9.08 L/100km over the last 6 months. Rather than using the trip computer, this is based on the actual amount of fuel (87 octane, "bronze") that I have put into the car, and the distance I've travelled. This is roughly 90% city driving.

    My mileage is best when it's warm enough that I don't have to use much heat, but cool enough that I don't use much AC. It's generally worse in the heat of summer (lots of AC), or in the dead of winter (lots of heat, so the engine keeps running), or in the rainy season (lots and lots of moisture, so I keep the defogger running, which runs the AC and sucks heat).
  • dmbfloridadmbflorida Posts: 38
    please post again if you calculate miles per gallon for American drivers. I seem to be "brain dead" this weekend.
    my mpg is about 26 running air conditioning constantly in hot SW Florida. I love this car. I do not use it much because I also have the Mazda Tribute "loaded" model (SUV) with hybrid engine,2008. it has been a good car but it was only available in CA and it is driven in Florida. The Mazda gets about 29 mpg.
  • skycaptainskycaptain Posts: 33
    Sounds like you take really good care of your cars. Keep me in mind if you ever want to sell one of your hybrids. I can't afford a new one but a good well kept used one from you is just as good to me.


  • kaperinokaperino Posts: 19
    Just had the big 90,000 mile done and replaced the water pump. She is still getting around 27.9 mpg. Still love her. Still live in the south so run AC on panic most days. Like the new model but not a lick of trouble except the cheap tires she first came with.

  • dmbfloridadmbflorida Posts: 38
    I do not wish to sell my only has about 34,000 miles on it even though it is a 2006 model. I am older and expect to keep this car "forever" as I have not had any problems and it seems so safe to me in addition to being comfortable.
    . I loved my Prius 2004 but it was uncomfortable to me because of the small size.
    My daughter, in Ft Lauderdale, might consider selling her Lexus 400h 2006 at some time because she has been unemployed and needs money. Her mileage likely is 50,000,,, I don't know..
    what is great is that the Lexus 400h 2006 looks like a new model.

    btw, in spite of the propaganda against Toyota, I still think it is a great car.

    D M Burke
  • I have a 2008 R400h. I've been averaging about 27-28 on the car using proper hybrid pulse driving techniques across a range of in-town and freeway driving (rarely about 60mph). On a flat 35mph road with limited stops, I can average in the mid 30s MPG.

    The on board MPG is off by exactly .5, every time - measured across 60+ tanks of gas since I got the car. The point is - MPG has been consistent for 18 months of use provided I use the same driving techniques, which I do.

    Last month, the mileage number started to go down - averaging around 26, and now I'm down to 22. In addition to that, you could sense the car was behaving differently. Engine was on more often, engine came on instantly when gas pedal was touched, and sometimes it came on for no reason, even when stopped with the hybrid battery charged.

    So I've tested different brands of gas for the past month - no change. Had an oil change, no difference. Since performance and behavior was consistent for 18 months and all of a sudden became dramatically different, I am concerned that something in the computer system has gone wrong.

    Today when I get home, I will try the 'fix' outlined in a Toyota service bulletin to reprogram the ISC - although this fixes a problem resulting from a dead or disconnected battery, and that didn't happen to my car.

    Has anyone else suffered a sudden and dramatic drop in MPG along with a change in car behavior? If so, did the dealer diagnose and problem and take steps to resolve it?
  • I bought my 2006 RX400h for $54,000 in Oct/2005 and as I commute a lot (a very lot actually) - interstate I put lot of miles on it Odometer reading shows 425,360 (on 8/24/2010) and even the dealer is surprised. I took very good care of my car (never missed a service). As i primarily drive on highway I used to get 28MPG in the first three years and the MPG decreased to 26-27 these days (after 350k miles I guess).

    But still the vehicle runs great, No problems whatsoever. Planning to trade-in next year (early 2011) for a 2010 or 2011 RX450h (for tax write in 2011)

    Any suggestions on how much I might be able to get on my car (assuming I hit close to 450k or half a million miles)

  • I bought my 2006 RX400h for $54,000 in Oct/2005 and as I commute a lot (a very lot actually) - interstate I put lot of miles on it Odometer reading shows 425,360 (on 8/24/2010) and even the dealer is surprised. I took very good care of my car (never missed a service). As i primarily drive on highway I used to get 28MPG in the first three years and the MPG decreased to 26-27 these days (after 350k miles I guess).

    But still the vehicle runs great, No problems whatsoever. Planning to trade-in next year (early 2011) for a 2010 or 2011 RX450h (for tax write in 2011)

    Any suggestions on how much I might be able to get on my car (assuming I hit close to 450k or half a million miles)

  • ronjoronjo Posts: 4
    How has your "in town" mileage changed over time ?? Did you ever need to replace the batteries? That is where I would expect a deterioration. (If you replaced, where and how much?)

    FYI: I have 2006 rx400h. Gets about 20mpg in town (sigh) - and I drive like a granny.
  • Hi...Did reprogramming the ISC worked for you? I recently bought used 2007 Lexus Rx400H and its getting 24.5 MPG. I am pretty disappointed with the mileage. Was expecting atleast 28MPG. The gas engine kicks in too fast at low speeds(5-10mph) even though the Hybrid battery is fully charged.
  • I ended up doing it twice, but it seemed to work - I've had two tanks average above 30mpg combined, and others around 28. I'm very satisfied with the mileage now - however I use pulse driving aggressively and keep my speed quite low. That's the only way to attain those numbers.
  • I called up the dealer and they have no idea abt ISC reprogramming...Are there any specific terms that dealer can understand....Also what is meant byPulse Driving!!! Never heard about that...curious to know...

  • if the dealer doesn't know about this, they are either stupid or lying or lazy. You can look it up at Google - just search for toyota hybrid ISC and hybrid pulse driving. There are a number of do-it-yourself posts on both.

    When you reset the ISC, you idle around and drain the battery until the engine comes on, then shut the car down. You turn off all accessories and climate control (nothing electronic should be on). Put the car in run mode (start it), press the brake pedal, put the car in drive, then while holding the brake pedal down, press the accelerator pedal down.

    The car will not move or rev much, but the engine will be on and start charging. Keep the gas pedal down for 40 seconds, then release it for a few moments, then down again for 40 seconds and keep doing that 40 on/10 off etc until the battery is fully charged (all green) and the engine no longer charges or revs slightly when you press the gas pedal down. Of course you're holding the brake pedal down all the time while doing this.

    Shut down, put your accessories back where you want them, then you can start up and go anytime. Learn about pulse driving to maximize your mileage going forward.
  • Sean, Here is the concept explained better han I can....Luke :shades:

    Pulse & glide overview

    Pulse and glide works like this: let's say you're on a road where you want to go 60 km/h. Instead of driving along at a steady 60, you instead accelerate to 70 (that's the pulse), and then coast in neutral with the engine off down to 50 (that's the glide). That's it. Rinse and repeat. And repeat. And repeat...

    By doing this, you're still averaging 60 km/h, but it turns out that pulse and glide is significantly more efficient than driving along maintaining a steady 60 km/h.

    If you're like me, it seems completely counter-intuitive. You're asking, "how can that possibly be more efficient than maintaining a steady speed in the highest possible gear?" After all, it violates one of the main commandments of efficient driving: conserving momentum.

    Why it works

    Pulse & Glide marathoners
    Prius MPG marathoners at the completion of their nearly 48-hour endeavour. (Source: hybrid newsletter)

    The secret is in the glide, and it's is best illustrated by the extreme Prius demonstration.

    The Prius is particularly excellent at gliding because under most conditions when the the accelerator is released below 40 mph, the gasoline engine shuts off completely and the transmission effectively freewheels in neutral (it's actually slightly more complicated than that, but stick with me). So, while gliding, it's effectively getting infinite mpg - it's using no gas at all.

    For that reason, the marathon drivers picked 40 mph as the upper limit of their pulse & glide cycle (33 mph was the bottom). So in order to achieve 109.3 mpg, they just had to average 54.65 mpg while pulsing gently from 33 - 40 mph. And it turns out, in a Prius, you can. So, assuming equal length pulses & glides, they traveled half the total distance of their trip getting 54.65 mpg, and half the total distance using no fuel at all. It averages out to 109.3 mpg.

    (Their driving was actually more complex than the simple illustration above, so their pulse vs. glide proportions were not necessarily equal. But for the purposes of understanding the basics of pulse & glide, it helps to think in terms of equal halves. The drivers also took pains to ensure they were pulsing and gliding in a very specific way that minimized the flow of energy to and from the battery pack - they were in effect going to great lengths to avoid using the car's hybrid propulsion while driving. Whenever braking, however, they sought to take advantage of the hybrid system's energy regeneration. Follow the links at the end of this article for detailed Prius-specific pulse & glide info.)
  • sunilbsunilb Posts: 407
    Our battery was changed shortly after we purchased it (2006 model year; CPO... bought last year). I noticed the gas mileage dropped from 24.5 to 21.9, I asked the dealership about this and they said that they performed it. Anyhow, I just did the ISC reset this morning and am hoping that it helps our situation. Honestly, I'm amazed that people are getting 28+ mpg.

    We live in a hilly area, so I know that doesn't help but also do a bunch of (flat) freeway driving and still haven't seen anything better than 25mpg. I haven't been doing any pulse driving (clearly).

    Btw, for the ISC reset, the instructions I found said that to only hold the gas down once for 30-40 seconds. Should I have cycled this more times?

    Also, it said to shut the car down and then wait 5 seconds then start it back up and wait until the engine shuts itself off (it will automatically run on start up).
  • Ms Burke, That's how I feel too. My daughter is about to have a baby and is looking for a reasonable priced used RX400 so let me know. My email is

    Kind Regards,

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