Lexus RX 400h - MPG-Real World Numbers

dmbflorida · July 2009

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.

ronjo · March 2010

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

kyxydj · March 2010

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.

dmbflorida · March 2010

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.

mtrs · July 2010

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).

dmbflorida · July 2010

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.

skycaptain · July 2010

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.

Regards,

Luke

kaperino · July 2010

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.

Kap

dmbflorida · July 2010

I do not wish to sell my Lexus...it 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

bocastephen · July 2010

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?

neoandem · August 2010

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)

Thanks
John

neoandem · August 2010

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)

Thanks
John

ronjo · August 2010

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.

sean_lexy · November 2010

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.

bocastephen · November 2010

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.

sean_lexy · November 2010

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...

Thanks

bocastephen · November 2010

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.

skycaptain · November 2010

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: Toyota.com 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.)

sunilb · December 2010

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).

skycaptain · December 2010

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 lukskybiker@aol.com.

Kind Regards,

Luke

skycaptain · December 2010

here is the correct email lukskybiker@aol.com

dmbflorida · December 2010

auxillary battery changed? my 2006 usually has on full A/C in SW Florida and average is about 26 -27 mpg with A/C...I suppose it would be better without A/C. I have gotten better and worse mpg...we live on flat land.
A friend bought a non-hybrid version of 400h (?RX 330 ??) and says she gets around 20 but I think that is an exaggeration...most drivers of the RX330 get around 13 - 14 as far as I have been told.
regarding batteries, I do not drive my 400h a lot so I have to be careful and drive it enough to not run the battery down. I had to get a new auxillary battery two years ago but it was in the warranty I think.

sunilb · December 2010

yes, I should have specified-- the battery changed was the auxilary (standard) battery.

Anyone have thoughts regarding the appropriate way to do the ISC reset (ie, number of cycles, etc)?

roman7 · December 2010

I have this car with 34K on it. Summer time shows around 28-30 mpg, winter time is 27-28 mpg. Drives 60% in h-ways and 40% in town. H-way speed 70mph.
I'm not an agressive driver.
I use all heater and AC when it needs!
It's better than many cars in the market!

rx400hawd · December 2010

I'm new to this forum today and have not reviewed all the posts, but you guys seem to have the potential of being more helpful than my dealer's service department...
I bought a certified RX 400h (2006) with 45k miles in Sept. 09. I love the car but the milage in-city has been very disappointing. I'm getting ~18-19 mpg in the city and ~24 on the Highway.
I was under the impression that a Hybrid would give better mileage in-City than on the Highway.
The service adviser at the dealer first told me the low mileage was because of using regular-octane gas. The next service I had another adviser who said that should have no influence on the mileage, and the service chief felt it may be related to the wider all-season tires (which the car came with from the same dealer).
My take is that when I spent the extra funds to get a hybrid, I would expect better in-city mileage than that. I have noticed that it does not take much for the engine to start up, when starting to drive. Often when I start the car the engine starts too (even if the battery indicator is near full). When braking I often note the gauge (on the left) not to dip into the blue zone, but it sometimes does - and I have not been able to find any related factors or any consistency.
So my question is - is this kind of mileage to be expected, or should I go back to the dealer and demand that they figure out what's the problem is?

ronjo · December 2010

I too have the RX400h(2006) model with the same 18-19city/24highway and I drive like a granny. My tires are the high pressure gas saver tires (Michelin) and it did not help. Disappointed as well. Some systems on the car are not fully electrical so the car will start if you need them - e.g. heater comes from engine heat (it's not instantly hot)-so car must start.
Please take it to the dealer and find out why 'bad' mileage. My dealer seems to fix things but does not know the technology to advise why. I talked to the designer of the Hybrid at a Football game (USC), and he said Lexus hybrids are tuned for performance and not best gas mileage; Toyota tuned for mileage. Still too low for me - please take it in and let us know.

bocastephen · December 2010

Those mileage numbers for both of you are unacceptable for this car, especially for city.

Most dealers refuse to do the reset I described earlier - not sure why, but their usual approach to mileage issues on hybrids is to become very hostile and blame it on the customer or say Lexus hybrids are not designed for improved mileage.

So - since I'm continuing to avg an indicated 29-30mpg actual, 65% hwy and 35% city, I know it can be done.

Do the reset I described upthread and learn about pulse driving. Make sure your tires are inflated properly (to spec, not overdone). Make sure you're using national brand gas - but it doesn't need to be premium (although running a tank of premium through once in awhile doesn't hurt).

delegator · March 2011

First, responding to the post above that thought most RX330 owners get 13-14 mpg. I have an RX300 (model year 2001) and have consistently seen 18-19 MPG in winter and 19.5-21 mpg in the summer overall. My commute is about 16 miles, 2/3 highway, so it's a reasonable mix. That's in NH. So, I don't think it inconceivable that a conventional RX400 could get around 20 if there was a good amount of highway driving in the mix.

Regarding dealer responses to low mileage, I had a chuckle at somebody being told that it was because they used regular unleaded. I heard the same fairy tale from my dealer: "your mileage should improve by about 10% with premium". He further said that it might take 2-3 tanks before I saw the benefit because "the oxygen sensor would need to recalibrate itself."

Poppycock. I changed to premium (made sure to get the tank below 1/8 4 times in a row, filling with premium each time) and then started measuring. My mpg with premium unleaded actually dropped by a full 1+ mpg.

I don't have an answer as to why you are seeing so much lower than advertised mpg, but I'm sure the dealer has a whole bunch of reasons that don't involve him doing work.

mattmansmitty · April 2011

I read alot of these posts before I bought my 2006 RX 330 (used on Craigslist) in January. I had found an RX400h same year and was tempted but my wife wasnt ready to buy so I held off and it sold. He claimed he got around 28mpg on a regular basis.

So with the 2006 RX330 my wife gets 14mpg! Which sucks!
When I drove it on the highway the best I got was 22mpg!
We've had it for about 3 months now...

Side note:
I own a Prius and get an avg of about 40 in the winter and 50+ in the summer. City driving it does worse than highway, I commuted in and out of DC for 3 days for training and it dropped to 34mpg in March (it was colder out). As soon as I was on the highway it jumped back up to 43mpg.
So Hybrids do worse in the city than highway, highway you can coast and are using a combination of electric and gas power at times. Unless you mash on the pedal which then you can hear the gas engine kick in.

Also about premium fuel vs regular in any car, CarTalk had this to say:
http://www.cartalk.com/content/features/premium/questions.html

And according to the RX330's manual it states, "If premium fuel cannot be found near you, regular fuel may be used for short periods." Consumer Reports also lists the 04-06 model's fuel type as regular, although the gas cap on the car states Premium Only... Not sure about the 400h's fuel type but premium doesnt make a difference in mileage unless the car absolutely calls for it, and even then it might not make a difference.

At 14mpg honestly I'd be happy with 24-28mpg, especially when we're gonna see $5-6 a gallon gas.

skycaptain · April 2011

mattman, I have a 2007 AWD RX 400h and I get a 28 mpg combined almost always except in the cold winter. In winter the engine runs more to warm up and I pretty much get a constant 26.5 mpg combined. The best city mileage I ever got was 33.8 on a 12 mile loop in 45 MPH stop and go.

Luke :shades:

sunilb · May 2011

So, the wife's 2006 RX400h AWD recently had the following done:

1- throttle body cleaned;
2- oil change;
3- new tires (Bridgestone Alenza); and
4- ISC reset done -- the tech did this without hooking the car up to the machine (revved the engine)

This was about 6 weeks ago and last week, we took our first extended road trip (SF->LA and back)... gas mileage has not changed... still in the 22-24mpg range. Note: I am going by the onboard display (not calculating it by hand)... I had reset the mpg counter at the start of our trip. Temperature was moderate (65-85 degrees) and there were some crosswinds and elevation changes.
I don't recall my average speed but driving on Hwy 5 generally means driving between 75-80mph to keep up with traffic.

Does anyone think that the ISC reset needs to be redone the other way? What else could be done to improve mileage (or is the very high mpg that some are getting due to living in flatter parts of the country?).

Lastly, whatever happened to Edmund's long-term test of the 2006 RX400h?

Appreciate any and all responses!

dmbflorida · May 2011

I get better mpg on flat land but I have a FWD 2006 400h and you have an AWD so this could a reason for difference in fuel economy. I have driven I-5 and know the elevation changes and winds North of Los Angeles but my guess is that your mpg drop is partially due to the high speed you are driving.
Maybe you will get better mpg when you drive a highway where you are not required to drive 75-80 mpg My mpg, with A/C in hot SW Florida, averages about 26 -27 mpg. However, when a grandkid drives my car, the mpg drops to about 24 mpg so driving patterns make a difference too. good luck.

normrl · October 2011

I experienced a sudden change in mileage from a constant 26.4 mpg to 30.2 mpg this summer. We had an "inverter pump" failure on I20 near Abilene, TX and had to be carried to FW for repair. When the new inverter pump arrived and was installed, we were back on our way to NM. Not for long we broke down again. Ultimately, the computer was wrong it was the radiator which was plugged. On putting a new one in, we were again on our way and saw about a .1 mpg each half day.

We did decline once we left New Mexico's mountain this Sept. to 29.6 mpg. It sure seems to me that something in the repair is responsible, but the dealer says no.

occupy · November 2011

I have a Lexus 400RX 2007 with 42K miles. I recently discovered I am only getting 20MPG in the city, and 25 Highway. Go figure. I went to Lexus dealer and ask them why I was getting this low gas mileage. They gave me some standard lexus answer like " It all depends on how you drive the car", and a whole bunch of other excuses. The service manager proceeded to tell me to set back the fuel gauge every time I fill up, that should help this situation. He set it himself, and I drove for 2 days, with still 20-21MPG. I am really steamed beyond steamed at this. I called Lexus corporate to explain the problem, and they advised me to take the car in to have the Hybrid system checked out and get back to them. Well, I took the car in and had a full diagnostic run on my car. My car came back with NOTHING wrong, as a matter of fact, they told me my car was in excellent condition. Well, we have got a problem here now. So I need to call them back. I paid 51K in 2007 for a hybrid that I thought was giving me the gas mileage it stated on my sticker . I still have my original sticker. If this is the case, I have spent way more for this darn car. Something is really fishy with this and I am going to get down to the bottom of this. Please if you are having the same problem, post it, call Lexus. They need to be held accountable. I am going to hold Lexus accountable.. I really wanted a Bentley, for what I think I have paid for this car if the gas mileage was not truthful, and as much as I love it, I could've gotten my Bentley. Who knows, after I finish with this, I may just get one.

ronjo · November 2011

What does the original sticker state ?
1) I have a 2006 RX-400h and get about the same mileage as you. My whole family says I drive like a grandma (slow), since I'm trying to get the maximum mileage.
2) I met a Toyota engineer at a football game and complained. He said Lexus is tuned for performance (it is a fast car) and not mileage. The Toyotas get better mileage with same equipment. But..I'm like you - why does it say on the sticker?
3) Disappointed. Trying to save gas, be green, encourage innovation (all with a price tag) and it falls flat.

Please continue you inquiry and post what you find ! Thanks!

mattmansmitty · November 2011

I posted to this forum awhile back to see what the difference was between the RX400 and the RX330 (which I have). When buying I did have the option to get a RX400 but opted against it since I already had a Prius and didnt want 2 hybrids just in case there were issues.

So that being said the RX330 averages anywhere between 13mpg and at best 22mpg! I dont remember what the sticker said but 2006 was BEFORE the reevaluation of the mpg estimates put out by the Fed. Supposedly the old tests didnt account for city driving and different conditions which lower full economy. The old setup was way off on every car, since the revamp every single car's mpg was lowered, even my Prius which was supposed to get in the 50's but really gets in the 40's. Also account for different times of year, hybrids dont do well in the cold or the extreme heat due to battery efficiency. My Prius will get in the 50's in the summer and the low 40's in the winter, sometimes in the high 30's.

So if you guys are getting 20-25mpg that's probably accurate compared to the non hybrid model. That and the hybrid adds a good 400lbs plus to the gross weight of the car.

Just my 2 cents!

tmtanalyst · December 2011

I just bought a Certified Pre-owned 2007 Lexus RX 400H, less than a month ago. I was on getting 20 MPG, which is completely not what I was told that I would be getting (28/26 city/highway) by my salesperson before I bought the car. I believed because it was certified by Lexus (a brand known for living up to quality) that I wouldn't have to be worry about get the correct MPG.
After a couple weeks of delay, I finally got the Lexus dealership to service it to look at the MPG issue. The service folks just called and said NOTHING was wrong with it and unfortunately it depends on how you drive and warming up car/heat. I tried to ask them about an ISC reset and they said they heard nothing about that. I told them I purposely drove extremely cautiously, minimizing the use of gas and trying to coast as much as possible before I had the car serviced, but it did nothing to improve the mpg. Thus the service response to me was completely unacceptable and said the best they could do is have my salesperson call me tomorrow as he was the one to tell me repeatedly that it should get 26-28 mpg. It is unfortunate that the service people and sales people act like they work at 2 different companies. After the service person said they didn't know what MPG the car should get, I said surely Lexus should have that it print somewhere, which they conceded and then I said hypothetically that someone in the world should be able to drive the car and get the 26-28 mpg that I was told I would be getting. She finally agreed that "somebody" should be able to drive the car and get that kind of MPG.
I made a conscious decision to buy the RX 400H vs another SUV which would be less expensive as I believed I would save on gas over the next 6-8 years that would reduce the cost difference. If a car is Certified by Lexus, it should live up to the Lexus brand standards, the poor MPG is not acceptable. George, my salesperson is a really stand-up guy and a man of his word, so hopefully when he gives me a call tomorrow he'll make things right by either fixing my car or replacing it. I am hopeful Lexus will do the right thing and make things right. I'll keep everyone updated, if Lexus or anybody else wants to try to help me resolve this issue, it would be appreciated.

mckb · March 2012

Thank you for this good description. After just purchasing a 2006 RX400h, you can imagine my disappointment driving on a road trip and seeing the mpg peak at 23. Mostly 22, and no different around town prior to the trip. I had done what I thought was the correct procedure according to the tsb, but I did not first drain the batteries as you state to do here. That made all the difference. Found this thread while at the hotel, and tried it the next morning... that second day of the trip, the average jumped 20%+ to over 27 mpg! Now I thoroughly love this car! It doesn't seem to make sense why this works, and is an odd quirk to the vehicle, but it certainly does make a big difference.

cvav1615 · March 2012

I own a 2006 AWD RX400h, and have been the sole owner and driver. I am more of a highway or country/windy road driver as opposed to a city driver. I have never felt that I got the full benefits of owning a hybrid, but never complained with the 25-28 avg MPG (my previous vehicle was a Ford Expedition, which averaged 10-12). I am not a 'gentle' driver, but not an Indy racer either. In the past 2 months, my car has gone from the 25-28 avg to 18-20 MPG. With the 15 gal tank, where I used to avg anywhere from 320-360 miles per tank, I am lucky to get 260-280. I have not changed the tires in this time frame, I use the same gas, from the same station majority of time, which has always been the premium blend. Tire pressure is fine, and tires have been rotated at 5000 mile intervals... Nothing has changed!! I am just puzzled on the significant change in fuel economy. Yes, it is winter here in SW PA, but the temps have been quite mild compared to previous winters, and my car is garage kept the bulk of the time. Anyone have any suggestions or opinions as to this change? Thanks!

skycaptain · March 2012

Dear Cvav,
I would try an ISC reset procedure to reset the battery charging logic. I have copied the procedure from an earlier post. Here it is...

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.

:shades: Luke

cvav1615 · March 2012

Thanks Luke, I will try this. Just one question, how will I know the battery is full, in the green, if I do not have the Nav screen on to show me the Hybrid system? Thanks!

avery1 · March 2012

Maybe the oil company changed the gas composition to be less polluting. Ethanol will reduce mileage.

skycaptain · March 2012

Cvav, You leave the screen on for this procedure so you see the Hybrid battery turn green....Good Luck!!....

Luke :shades:

ahaber · October 2012

I just purchased a 2008 RX 400 H . the millage is great in city 25 mpg.

The problem with consumption is how you drive , when I am driving is 25mpg when my son driving is 19 MPG

equinelover · December 2012

Dear Luke: Merry Xmas! My Rxh 400 2006, died on me yesterday with two messages Check VSC and Hybrid system. Would the above procedue help me so that I can get it to the mechanic? I was supposed to take into the shop last week but scheduling got the best of me, the maintenance required light went on and with the holdiays couldn't get there. My car and I have been through alot and its been serviced regularly "old blue" has been through many a bad snow storm and icy roads and has been pretty good on the mileage too.

Best,
Alice And Happy New Year All!

88keyes · January 2013

About how long does it take to recharge the battery while doing the 40on/10off? Just bought a 2008 rx400h and the mileage is lousy and I've been really conservative in my driving.

clintonp · May 2013

If you live in a cold weather climate the gas companies change the make up of the gasoline to aid starting in cold weather. This gas reduces the mileage on most vehicles and especially on hybrids. September is the month when cold weather gas is introduced and ends in May. I had a Prius and I got 51 mpg I summer and it went down to 41 in winter.

dannie890 · November 2014

I have a 2008 RX400h and I am getting 22-23 for mostly "suburbs" driving. I get closer to 25-26 on the highway, assuming speeds not over 70 mph. I was really disappointed with the lower-than-sticker advertised mileage until I realized: 1) city and suburb driving are not comparable. While I have frequent stops, the speed limit is 45 mph and the traffic actually moves, so it's not true "city" driving, 2) I make a lot of short trips which reduces the mpg since each time the motor has to warm up, it uses up gas and doesn't run on the battery, even if you go really slowly, and 3) running the heater or the a/c (I do one or the other most of the time due to local weather) will also decrease the mpg.

I recently drove the new RX 350 and averaged 17 mpg in the same type of driving. So compared to those number, my 6-year old RX400h is doing pretty well. Still, had I known that my mileage won't be higher than the 22 mpg or so, I am not sure I would have invested the amount of bucks I spent on this car. Together with its "consumption" of tires, which is a whole other issue and another thread in this forum, I am beginning to think about selling this car.

Lexus RX 400h - MPG-Real World Numbers

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