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Lexus RX 400h: Driving Tips & Tricks

PF_FlyerPF_Flyer Pennsylvania Furnace, PAPosts: 5,854
Have a great tip on getting the most mileage performance out of your 400h? This is the place to share them with your fellow owners!

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  • rocky7rocky7 Posts: 13
    Does anyone know if it’s normal for the RX 400 to shutoff if you stopped for a length of time.

    I pulled over on my street to talk to a neighbor about our new car. During what I guess was 15 minutes the engine came on two or three times. My guess was to briefly charge the batteries.

    At end of what I guess was 15 minutes the vehicle entirely shutoff. I restarted it right away. Only the battery seemed to be on. About 5 minutes later the car shut down again.

    I started the car and was able to drive it home.
  • sinepmansinepman Posts: 137
    Totally normal. The vehicle still uses power when in park (electrical etc). A/C has a particular high drain. Once the battery gets to a certain state of charge, it will automatically signal the engine to kick in to began the charge process. This protects the battery to avoid LOW levels of charge which would effect its life cycle.
  • rocky7rocky7 Posts: 13
    The engine kick in as it did a few times during the 15 minutes makes total sense. My concern was the vehicle shut down entirely after 15 minutes. Including radio, dash instruments, etc. It acted like after 15 minutes I needed to reboot the entire car. When it shut down after 5 additional minutes, I need to restart the vehicle.

    If the engine came on periodiaclly to recharge thesupplement the battery drain or recharge, that makes sense. Not to have the vehicle shut down entirely first after 15 minutes and then aftrer 5 sdditionl minutes.
  • hongchohongcho Posts: 28
    My concern was the vehicle shut down entirely after 15 minutes. Including radio, dash instruments, etc. It acted like after 15 minutes I needed to reboot the entire car. When it shut down after 5 additional minutes, I need to restart the vehicle.

    This does not sound normal, does it? Have you talked to your dealer about it?


  • wwestwwest Posts: 10,706
    You can avoid the extended warm-up by turning the climate control completely off. Even if there is no heat "demand" the engine water jacket is still used to heat, moderate, the A/C's cooling level.

    I think I have seen a note pertaining to our Prius that says you can set the A/C to run in "demand" mode wherein it does not need the re-heat pass through.
  • headlessheadless Posts: 50
    I got my RX400h last of the first at the dealership and in the area. I was so happy to get it...but since then, I'm SO disappointed...

    I don't know how upset I should be at this point. I filled up my tank at 301 miles and checked to see I am only getting 23.4 mpg. This is downright horrible for a hybrid.

    I don't understand it. I am not running the car hard and am accelerating as I would under 'normal' driving conditions.

    I spoke to my car dealer and they said to allow 1000-2000 miles for a breakin period. I don't recall reading this in any of the reviews, as it appeared that everyone else was getting 27-31 mpg right 'out of the box.' I don't know what to do at this point? Should I sit and wait another 1000 miles to see, or should I contact Lexus and 'demand' they take the car in and see what the heck the problem is. My miles are a mix of highway and light traffic...

    I have a few topics of interest:

    1. The electric motor rarely if ever runs on its own. Any acceleration and the motor kicks in....and I'm not gunning it...if I'm under 5 mph, maybe it's only the electric...but otherwise, unless coasting, it seems like the motor is running...
    2. The battery meter is NEVER full...ever.
    3. The V6 seems seriously inefficient...whenever I accelerate, it looks like I'm under 10 1997 Infiniti does better than this!

    I had such high expectations for this vehicle and I am so disappointed. I simply don't know what to do and everytime I get in the car, I'm stressed out with the crappy mileage my hybrid is delivering. Had I known it'd be so low, I would have opted for another vehicle. I am not impressed with Lexus at this point...this is my first this rate, my last...I would like to get the posted mileage so I can really feel like buying a hybrid was well worth it....

    Any good advice out there for a disgruntled new Lexus owner? :(


  • cyclone4cyclone4 Posts: 2,259
    If you are sincere in what you state (I have no reason not believe you at this point) and you are not some kind of a MB guy trying to discredit Lexus, then I would say that something is wrong with your RX400h. Bring it to the dealer asap and have them look at it closely. As far as the battery meter is concerned, I don't think that it's neccessarily suppose to show it as totally full.
  • headlessheadless Posts: 50
    I am not trying to discredit fact, I had a $1000 deposit down for this car for about a year...been waiting what seems like forever for this SUV...

    I was soooo excited to get mine but after driving it now 300 miles, I have yet to see any of the hybrid benefits...

    The salesperson keeps telling me to wait for the breakin period of 1000-2000 miles, but I'm finding it harder and harder to believe I'm going to go from 23 to close to 30 mpg...just seems like a leap of faith...and every time I get in the car, I'm stressed to even look at the mpg...I'm simply NOT a satisfied customer up to this point in time!

    She (the salesperson) said that they (Lexus) cannot do anything with the car until the engine is broken in...however, she also assured me that if the car does not get the mileage that was posted by Lexus, they'll 'dissect' the car, and re-assemble it until it does what it's supposed to do...she remarked Lexus stands behind their products 100%...

    I know Lexus is number 1 and has been for years...but that's not helping me right now...I'm just really stressed out that MY particular RX400h is performing well-below standards...almost like the Murphy's Law I was telling everyone I was going to get good performance and good mileage in my hybrid and my friend's Honda Odyssey is killing my mileage...I'm embarrased to tell anyone I got the hybrid...that's how pathetic it is (at least in my mind...23 mpg...come on!)

    I feel 'stuck' right now...frustrated and angry that my 50k+ hybrid SUV is barely performing better than a RX330. I feel, to this point, I have wasted a lot of money.

    Anyone else there with the same problems? I read EVERY review on the car...not ONE ever stated a breakin for good fact, every review remarked mileage around 30 mpg. I'm NOWHERE even remotely close to I said on earlier post, I feel, at this point, I've wasted my money...and am pretty bitter about it, if you can't tell...

    I just need some reassurance that my car is going to get the mileage Lexus of this point, Lexus has not done much to assure me other than to tell me to drive it a few thousand miles before worrying about this consistant with hybrid thinking? It sure isn't making me feel better about my over $50k purchase...

  • cyclone4cyclone4 Posts: 2,259
    I can tell you are in total agony. Officially, I don't think there is a break-in period as such. My dealer told me not to use the cruise control for the first 100 miles and that's about it as a break-in period. However, there have been some posters here that do indeed claim that the gas mileage will get substantially better after the first couple thousand miles of driving. Are you paying close attention to the consumption meter/screen so that it forces you to be very light with the accelerator? I'm confident that your problems with gas mileage will be rectified by Lexus in due time. Good Luck!
  • falcononefalconone Posts: 1,726
    I also think you should wait for a decent break in period before you jump to conclusions. I've read some professional tests of the vehicle and it appears some of the journalists are getting expected mileage. I don't doubt what you're saying, but I 'd conduct a test after the break in period. Take a nice 60 or 70 mile drive at 68 MPH with cruise control on. Note what your mileage is over that stretch of road. Also take note of the prevailing winds and so forth. I bet you're going to get at least 27 or so MPG which you should be pleased with. As far as the battery is concerned, I believe it is operating normally. If it is anything like the Prius battery, don't expect it to be fully green all the time. Most of the time under normal driving conditions, it will be on the high side of the blue bars. This is an intentional design to keep the battery at optimum performance.
  • dmcmahondmcmahon Posts: 26
    Remember you won't get great mileage in highway driving; there, the gas engine is still having to lug around a 4500 pound SUV. The 30mpg figure was for city driving.

    Bottom line is that Lexus positioned their hybrid system as a performance enhancement. If you wanted maximum mileage, a Prius might have been a better choice. I know, I know; too small, not luxurious enough; exactly the reasons I signed up for the RX wait-list.

    Just in case anyone from Lexus reads this board, I think they need to refine their green car strategy a bit. The RX is a good first step. How about a crossover (Mercedes E350-like) vehicle weighing only 3500 pounds, and possibly with a more efficient V6 gas engine? How about a plug-in option so that you can keep the battery charged from AC and eliminate that "warmup/recharge" period some people are reporting?

    Seems like I might just be better off waiting to see how the RX and other hybrids evolve over the next few model years.
  • gagricegagrice San DiegoPosts: 28,848
    How about a crossover (Mercedes E350-like) vehicle weighing only 3500 pounds, and possibly with a more efficient V6 gas engine?

    How about the "R" class MB? With the planned diesel hybrid I may just jump onto the hybrid wagon. Especially if it gets 40 MPG highway. It looks like it will be aimed directly at the RX400h. If you are more of a highway driver than city driver it may just be the ticket.
  • headlessheadless Posts: 50

    Thanks for your reply...agony...definitely...

    I think I am being light with the seems that if I accelerate from a light on level ground, the engine will always kick in after a second or way around that unless I want the person behind me beeping at me!

    I did drive it on the highway a lot today but at a speed faster than 70 my area, I'd get run over at 70...the mpg kept decreasing until I figured I put enough 'higher speed' on the engine and backed off to about 68 mph and put it in cruise...the mileage did creep up from 23.5 to about 24.00 (on the screen)...however, when I filled it I found that the mileage divided by the 12.85 gal. I put in averaged 23.4 my unhappy suprise...

    I realize also that the hybrid engine (motor) will break in more slowly as the electric will help out from time to makes sense that at very low speeds, the electric will help out...I always figured it'd run on electric only unless you hit about 20 mph...this is not the case...

    May I remark at this time that the rest of the vehicle is awesome...the ride comfort, navi, stereo quality (non ML), adaptive lighting, etc...all perform per Lexus high standards...

    I'm just hoping that I don't have to drive like grandma to get good mileage...if others have heard of longer breakins to achieve 27 to 31 mpg, then I guess I just have to wait and see...

    BTW, the phone bluetooth is awesome...finally got my treo 650 to send my entire phone book into the one-touch dialing my favorites, I can make calls while in motion...otherwise, no go...

  • headlessheadless Posts: 50

    Thank you for your reply....

    I am certainly over 17.5 you can tell though, I'm getting impatient...I figured the great mileage would be achieved immediately...I guess I am finding that I am wrong with that thought...

    I will check out the other forums you mentioned...I am glad I'm not the only one with this concern...I realize adapting to a hybrid takes time, but I figured 'normal' driving would still allow good mileage...I guess I'm just going to have to calm down and give it more you said, 300 miles is not a few thousand and things should 'loosen' up with time...

  • headlessheadless Posts: 50

    Thanks for the battery tip...I had a lot of things going through my my particular RX was a dud...if it's normal for the battery to stick on upper blues or an occasional green, then I'm in the 'okay' area.

    I did drive at 68 mph today on cruise for about 10 mileage indicator did go from 23.5 up to I think it was 24.0...but, when I filled it up, and did the math manually, it did only show 23.4 overall...that's why I was disappointed...

    I guess I'll have to wait until I hit about 2000 miles to really 'worry' about it...

    Most of my driving is in 25-50 this 'bad' for efficiency? I am able to coast at times...and coasting is where the hybrids do best, right?

  • brightness04brightness04 Posts: 3,151
    23-24mpg average is not that bad. My 3.3L Highlander only got 16mpg when brand new, now it's up to 19mpg or so after a year and 17k miles. The per centage increase is the same 50%, whether it's 16 --> 24 or 20 --> 30, although the latter sounds better. In reality, if you drive the same 15k miles a year, the former (16 -> 24) saves more money.
  • cyclone4cyclone4 Posts: 2,259

    Hang in there! From everything we hear from all these knowlegable posters, things will get better with your gas mileage. Now, why I have been averaging more than 31 mpg in the city and about 27 on the highway while you have been averaging about 6mpg less, I have no idea. By the way, I have been doing normal city driving (stop and go, etc., etc.). I have now done enough of this to be confident in the results I reported on a couple of posts above.
  • headlessheadless Posts: 50
    I never realized it could take THAT long to break in an engine...I realize the electric motor helps, so the gas motor may take a little longer...luckily, the RX uses cheapy gas...I'd still like to get it up over 27 mpg average...that's what I thought it would do 'out of the box.'

    My friend's Infiniti FX35 uses 93 octane and gets combined 18, I guess with, at this time, 23.5 mpg and 87 octane, I'm not doing so, the RX isn't giving up much performance...the thing is pretty fast...(yeah, yeah, and I'm not gunning it to test it all the time!)

  • wwestwwest Posts: 10,706
    is a function, strictly, of battery pack internal resistance to high inrush charging currents and the upper operational voltage and current limits of the solid state motor "drive" and energy recovery components.

    Since the source of the regenerated energy, the drive motors, are not the primary limiting factors I would doubt if it would take anything more than a single 50KW motor to recapture all of the energy that CAN be recaptured in the RX400h during the most optimal slowing or braking circumstance.

    For instance, quick, short distance stops would result in very little charge for the batteries.

    It's most likely that learning to lift your foot, completely, from the gas pedal when you first see, realize, you wish to slow or stop will result in the best operational fuel economy one can attain. The heavier you apply the brakes the least likely it is that the batteries can accept the fast charging rate that a quick stop requires.

    So, quick off the throttle and light on the brakes wins the day, fuel economy wise.
  • karkuskarkus Posts: 11
    A 400h owner above said he was accelerating slowly but still getting bad mpg .. that's a common mistake when driving full hybrids (Toyotas and Fords). The best acceleration for good mpg has been described as "brisk". Don't floor it, but do accelerate reasonably fast. Unlike in regular automatic cars where accelerating quickly is not that great for MPG, full hybrids actually work better that way. Here's why: The engine is most efficient at high RPMs (true in pretty much all cars). So In a full hybrid, it is better to run high RPMs to get up to speed quickly, and then drive/coast with engine off (and just using the battery) instead of accelerating slowly which will run the engine at low inefficient RPMs the whole time.
    This has been verifed by various Prius owners (and the 400h hybrid system should behave in the same manner). Some people even go so far as to use pulse driving - hit the gas, let it coast, hit the gas, etc. - but that's taking it a little far -just use cruise control and let hills accomplish the same thing for you.
    Regarding the best speed for MPG - in a Prius it's 30-40 MPH (one guy got almost a 1000 miles on a tank at 35 MPH). I don't know what it is in a 400h but I'm guessing it's similar.
    Another tip: Brake gently (or let it coast) - that puts the most juice into the battery. Hitting the brakes hard activates the regular (friction) brakes.
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