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Methinks the "flaw" is the result of Toyota and Lexus assigning too high a priority to improving fuel economy. There may also be some modivation to reduce the number of accidents due to loss of control from engine compression braking on the drive, front, wheels. In any case IMMHO these transaxles are FAR too quick to upshift in throttle closed coastdown circumstances and that oftentimes results in being in too high a gear ratio if the driver suddenly re-applies pressure to the gas pedal. The result of that, for vehicles with hard connections from the gas pedal to the throttle valve, is that the engine RPM is rising at the same sime the transaxle is downshifting. Sorta like "feathering" the clutch with a stick shift with the throttle wide open, except with an automatic you don't get that horrid clutch burning odor until you check your ATF at about 40,000 miles. In 2004, and after, the RX uses the e-throttle control firmware to delay the onset of engine torque development and therefore "protect the drive train".

First, the filter is a simple screen filter and as such isn't likely to need changing out. Second, if you DIY a 5th quart should be drained via the diff'l drain plug. And last, were I you I would drop the sump pan and clean out all the clutch friction surface debris there. My first time, at ~40,000 miles, I only drained 4 qts, not being aware of the diffl drain plug. And then a week later when I discovered my ATF was still looking and smelling burned I repeated the process but this time drained 5 quarts and cleaned the sump pan. Now at 50,000 miles and looking good to go.

For some unknown reason all Toyota or Lexus vehicle will automatically disable VSC, Trac, etc, when there is an engine diagnostic indication. Fix the engine problem and the Trac off light will go out.

The bumper "facsia" is plastic. Wasn't sure about the body and door bottom panels so I took a refrigerator magnet out to my 2001 RX300. They're plastic.

First, some of us believe that Toyota/Lexus has instituted a "secret" warranty involving premature transaxle failures. So "push" the dealer as hard as you can to get the costs of repair covered. IMMHO these failures are the result of a firmware flaw in the engine/transaxle ECU. These transaxles upshift rather quickly during brief periods of throttle closed coastdown situations. If the driver happens to reapply gas pedal pressure just as the upshift is initiated then the engine torque level will rise with RPM just as the transaxle begins its new shift sequence back down into a more proper gear ratio for acceleration. In 04 and later RX models premature wear of the transaxle's internal clutches is prevented using a DBW system to keep the engine RPM from rising until the clutches are firmly and fully seated.

Do you mean to say those aren't really plastic bumpers on my RX??

Unless you have the dealer set the available c-best options your A/C will operate all year around excepting only periods of freezing of sub-freezing weather. Even if you turn it off manually it will still operate, with no indication of such to the driver, in defrost/defog/demist mode. The diagnostic indication is the result of the A/C compressor drive belt slippage due to being soaked.

I did a drain and fill, 4 qts, at ~40,000 miles and about a week later the ATF was again looking and smelling burned. The second time, 5 qts, I also drained the diff'l via the separate drian plug, dropped the sump pan and cleaned about 1/8 inch of what appeared like ground up pencil lead from the bottom of the pan. Now at 50,000 the ATF is still looking very serviceable. But I really don't think any ATF maintainance program will alleviate the instances of premature failure in these transaxles, just delay them due to ATF being more capable of doing its part.

No, as an example of the correct way the Volvo XC90 AWD system biases the engine torque to the rear until the apex of the turn/"curve" is reached and then starts routing the engine torque primarily to the front after the apex. The traction coefficient of the front wheels will be at its most stressful prior to and having reached the apex of a turn/curve. On the RX400h the ICE/hydrid drive torque is clearly biased toward the front wheels and therefore the most likely instance for the front tires to lose traction is at the height of lateral + drive torque. The apex of a turn/curve on a slippery roadbed. So at the instant of approaching the apex on a slightly slippery surface the front wheels slip due to the contact patch being "over-stressed" and as a result the Trac ECU instantly reallocates drive torque to the rear. The result is probably compariable to the problems with the early models of the Porsche 911, total and complete loss of control.

Yes, and a failure of the clutch relay should NEVER result in the lack of heat unless there is another problem.

The BMW X3 is RWD engine torque biased and will therefore be more stable overall and especially so when the roadbeds are slippery, mud, snow or ice covered. The Rx400h will have much better fuel economy but your life will be at risk each time you take it out in adverse conditions. The ABS system, ECU, can easily detect that a wheel or wheels is/are slowing/stopping too rapidly during braking and therefore moderate the braking pressure so you can maintain directional control of the vehicle. No such capability is available to detect that a driven wheel under engine drive torque, cruising or accelerating, is "about" to break traction. If the primary drive wheels are at the front then you will already have lost directional control at the instant the Trac system detects traction loss and switches some "drive" to the rear motor. Also keep in mind that while ABS can moderate braking pressure so you can more easily maintain directional control it cannot alleviate engine compression braking at the front drive wheels nor braking due to regenerative effects of the front electric drive motor/generator. If I ever purchase an HH or RXh it will only be after I design a modification such that during acceleration the front wheels always appear to "slip" and therefore the ECU will automatically provide primary drive at the rear. I have no idea where one would begin in designing a method to quickly alleviate hybrid drive torque and/or engine compression/regenerative braking on the front wheels during coastdown should the surface prove to be slippery. An X3 for me!

I'm thoroughly puzzled, why no heat? FedX me the relay and I will fix it.

When spraying anything into the outside air inlets at the bottom of the windshield its a good idea to be sure the system is not in recirculate, the blower motor is on a medium speed and the rear windows are down. It helps tremendously if you park under shelter and can lower the windows slightly each and every night.

Check out the EED device at airsept.com

Look for a wire that is chafted or tie-wrapped to tightly to the metal frame.

Is the water valve moving incrementally as you adjust the temperature or in "bang-bang" servo fashion, going directly from fully open to fully closed only when you get to max cooling? If the latter then the IAT, cabin interior air temperature sensor just above the drivers right knee is open. You will also see some of this effect if the OAT, outside air temperature sensor is open. Open IAT will indicate that the cabin is extremely COLD and open OAT will indicate the outside temperate is extremely LOW, below freezing. OAT is mounted on the back of the front bumper re-enforcement just in front of the center of the radiator/condensor assembly. If, as your temperature selection passes through the actual cabin temperature, the water valve moves incrementally then yes, the blend door is no longer connected to the servomotor and you have a rather difficult problem. It is not easy to access the blend door.

Or... Many of the newer transaxles will not shift into OD until the ATF is warmed to a high enough temperature for optimum operation. For these transaxles there is a thermistor that measures the ATF temperature and if this thermistor is open the ATF will always "appear" cold to the ECU. Newer models detect "out of range" for sensors but I don't think yours does.

Each seat positioning servomotor has a feedback method and it sounds as if at least one of the feedback signals, if not the reference itself, is shorted to the seat frame (not enough current available to blow a fuse). Shorted reference and all of the servomotors would go absolutely bonkers!

The simplest way to adjust HID headlamps is to adjust the rear vehicle heighth sensor at the rear axle. One adjustment, both headlamps.

You have to be fairly careful about which replacement bulbs you buy. For instance those labelled LL, long life, may not draw as much current as the OEM bulb and therefore trigger the bulb failure circuit.

How did you manage to keep the fog lights on with headlights off? Unless you modified the circuit that is not possible.

Yes, the A/C will be more efficient in dehumidifying the airflow if recirculate it used. But a serious trade-off is involved here. If you use recirculate continuously then there will be little or no cabin atmosphere "flow-through". With human metalbolism being as it is the cabin atmosphere will slowly become more stale and humid. In order to improve MPG when using the A/C year 'round, modern day vehicles, even non-luxury ones, are extremely well insulated and sealed. Even the "opening" of the cabin atmosphere outflow "exhauster" has been downsized to retrict the outflow of previously "conditioned" air and thereby reduce the need for the more A/C compressor cycling. But the real danger is having the A/C compressor shut down if or when the outside air temperature declines to or nearly to the freezing level. Once the A/C shuts down, and it will (generally with no noticeable indication, no aleart or alarm, to you) the cabin atmosphere, at your ~70 comfort level, will quickly result in the evaporation of the previously condensed moisture still on the evaporator vanes, into the cabin airflow. Talk about sudden and complete windshield fogging...!! So yes, the act of using the A/C to aid in defogging the windshield or keeping it defogged will oftentimes be helpfull and certainly not harmful in and of itself. But look what happens if and/or when you turn it off with all that previously condensed mositure still on the evaporator vanes. It will often quickly evaporate into the airstream and thereby into the cabin. Cars with air conditioning have always endured episodes of mould and mildew odors and windshield or window fogging, but in about 1990 the industry started changing automotive designs in ways that inadvertently led to a dramatic increase in these instances. Better insulating, sealing and sound deadening materials all result in more "containment" of the cabin atmosphere. Intentional downsizing of the cabin atmosphere's exhauster port so "conditioned" air could be held, maintained, within the cabin longer. At the same time due to growing space limitations (no pun intended) within the front dash area the A/C evaporator was downsized again and again. So nowadays we have 10,000 square inches of evaporator cooling vane surface area collapsed into a very small space, think "sponge". Operate the A/C, give these modern day A/C evaporators 24 hours to "dry" out in a warm garage with the windows closed, and you still have about a pint of liquid left, as a thin film of condensate, on those vanes. Another quart or so will have evaporated off the vanes in that 24 hours but is in all likelihood still within the A/C plenum area in airborne vapor form. The atmosphere within the plenum is very likely super-saturated with moisture. So you start down the road the next "cool" morning, the system blower doesn't start up until the engine water jacket has reached 130F, 2 to 5 miles down the road, and POOF, your windshield is suddenly fogged over to the point where you have absolutely no forward view. The windshield fogging problem is further exacerbated by the uniqueness of automatic climate control designs by NipponDenso, Denso US, used exclusively by Toyota and Lexus and many other vehicles of asian origin. Denso UDS actually holds a US patent on this unique design, cooler system airflow predominantly to upper cabin areas and warmer system airflow restricted to footwell and lower cabin airflow areas. Regretably while inherently a good concept its implementation in most cases inadvertently results in the inability to quickly defog or demist a window or windshield. In order to get warm and dry airflow to the interior surface of a fogged over windshield the internal system airflow must be reversed, baffled, at the footwell plenum outflow exit, if order to force the "reheat" flow to the windshield ducts. So Airsept's EED device will have a substantial market for the foreseeable future and not jsut a few accident will result from episodes of inadvertent and sudden windshiedl fogging in cool or cold weatehr conditions. In the meantime either find a way to disable, completely, the A/C compressor during the winter months, or park your car in a warm garage each and every night with the windows open slightly to allow the previous day's condensate to evaporate and allow convection airflow to remove most of the resulting airborne moisture.

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Your 16.9mpg is also typical of "city" in my 2001 AWD RX300.

If something isn't broken why insist on fixing it...?? Unless you have been using an intake air filter not OEM or equivalent, say K&N, in which case I fully understand.