wwest

Wow, premium makes that much of a difference? Of course, I was inflating the number, but I do know that higher intake air temps can easily cause my Corvette's ECU to !Removed! timing enough to reduce RWHP by 10. Many years ago, My family and I were in Las Vegas in August, driving our Nissan Quest van. It was pinging so badly on regular gas (never a problem in San Diego) that it felt like power was cut in half. General rule of thumb: If your engine is going to ingest >100F air, use premium fuel. But isn't the engine/ICE in the RX400h so heavily derated already that it would be practically impossible to encounter ping/knock due to low grade fuel...?? Your Corvette, and my Porsche, both have high enough compression ratios that the engine control ECU must somehow automatically "derate" the engine if low grade fuel is used. In my case the factory informed me that the procedure would be that the ECU would first enrich the mixture to prevent, alleviate, knock/ping.

So, I have a 99 RX300 FWD that I've owned for a little over a year... and my tranny recently went out. I bought the car out of Phoenix, and it had about 114K on it. It ran and drove perfectly over this past year, and I've racked up a ton of miles (now at 136K) with a long commute and driving my life away in it. About a month ago I noticed a slight whine upon start up, but then it went away when it was warmed up. I changed the fluid and kept an eye on it. Over weeks the whine got louder, and it was pretty obvious I was loosing a bearing or the pump in the tranny. It still drove great, but I added in some Lucas fluid to see if that would quiet it down. It did... a little. But a week or so later it started to slip and lurch between gears. So, I brought it to my trusted shop here in the Portland, OR area: Todd's Import Automotive. These guys run a clean shop and have always been fair. So, they did some inspecting, and sure enough, the tranny is on it's way out. Now these guys don't do tranny rebuilds in-house, but rather they work with Howard Engineering http://www.hecreman.com/quality_control.html for their rebuilt transmissions. They said they've never had one come back that they installed. I would rather buy a tranny from a remanufacturing business where rebuilding key transmissions are their core and specialized buisness, rather than going to some local shop and having them do a one-off rebuild. I'd almost trust a specialty shop over a Lexus rebuilt tranny, too. Anyhow, the total for the new tranny and swap is coming in at $3800. It's a chunk, but with a new tranny and a nice warranty on it, I think I should be set for some time to come. On another note, I've read all about the tranny failures in the 99-00 RX300's and I've read where people say it's because of the design and that it's essentially a Camry drive train in a much heavier vehicle (possibly from excessive heat build up). But what about the Sienna... they use basically the same powertrain (the 1MZ-FE engine), and an XLE Sienna is 3825 pounds (according to Edmunds.com), where my FWD RX300 is only 3692 pounds. I haven't read about any significant number of failures on the Sienna, and it's a heavier vehicle running similar powertrain (transverse mounted 1MZ-FE engine with a transaxle). Hmm. I've also read that a lot of the failures are because of the upshift programing in the tranny telling it to shift too soon, leaving a lot of torque load cranking through the tranny. This I could see, so I always drive with my tranny in the PWR setting... that leaves the tranny nice and responsive and shifts right where it 'feels' like it should. Anyhow, add me to the list of tranny failures, and this one in a FWD model. It'd be nice if Lexus helped paid for the repair, but since I'm getting the tranny from somewhere else, and because the vehicle is 9 years old with 136K on the odo, I think I'm on my own to cover this repair. " a Camry drive train in a much heavier vehicle.." Well, not really.. It appears that the design engineers, when designing the RX drive train, started out with the Camry's engine and transaxle. Apparently it soon became clear to them that the transaxle needed to be more robust, "beefed up" as it were, for the extra duty, weight, power, and AWD to boot. And then there was the issue of not very much room for more robustness in a vehicle with a sideways mounted engine and transaxle. So something had to go..GIVE. The engineers decided that with a minor level of reprogramming of the firmware the ATF pressure holding, "sustaining" accumulator could be abandoned from the design, obviously leaving more room for more robust gearsets and clutches. The fly in the ointment was that driver's don't always follow the "rules", especially rules that the manufacturer is extremely reluctant to publish. As a result of the "abolition" of the accumulator the newly designed transaxle could not support two gear changes in quick sequence with the engine nearly at, or actually at, idle. There is a TSB issued for the Camry in the spring of 2003 that very adequately describes the three most common instances wherein this has become a problem. Basically the situation occurs when you lift the gas pedal slightly, the transaxle upshifts, and now you quickly re-apply pressure to the gas pedal to return to acceleration mode. The WORSE case is if you begin by accelerating moderately, then completely lift the gas pedal, close the throttle, the transaxle upshifts accordingly (or for really worse case the transaxle only "begins" the upshift) but now you wish to quickly accelerate again and aggressively depress the gas pedal. For the 99-03 models the engine RPM begins rising immediately in response to the throttle position, but the newly REQUIRED downshift may not complete for another few hundred milliseconds. For the 99-00 model years the result, OBVIOUS result, is premature transaxle failure. "..excessive hest buildup.." By the time the '01 was to enter production the engineers had realized their initial mistake and made a QUICK fix, a MISTAKEN quick fix. They increased the pumping capacity of the gear type ATF pump so more volume/pressure could be supplied even with the engine at idle. That, of course, again, OBVIOUSLY (in hindsight) resulted in localized overheating of the ATF and that in turn resulted in the factory recommendation of a change in the ATF drain/fill interval from infinity to eveny 15,000 miles. But the inordinately high premature failure rate continued. Also obviously, it was about at this point that someone (beancounters, no doubt) decided that building a less expensive transaxle absent the accumulator could be spread across the entire FWD and F/AWD product line. It was also about this time that the "protect the drive train" solution, FIX, was arrived at. By the time the RX330 and Sienna AWD arrived on the scene DBW, E-throttle, had been adopted to prevent the engine RPM from rising in response to gas pedal pressure if a transaxle gear change, or two, was in process or upcoming, in the "que". Oh, not sure if this really relates, but also by the time the RX330 and Sienna AWD rolled out the VC, Viscous Coupling, previously used in the RX300 series to provide "full-time" AWD capability, had also been abandoned in favor of TC, Traction Control, braking to provide AWD capability only on an "as needed" basis via a "virtual" center (and rear??) LSD.

You can improve your FE pretty significantly by running your A/C without using the reheat/remix mode. Simply set the system to MAX COOL and RECIRCULATE and then use the blower speed manual control to adjust the cabin temperature to your desired comfort level. It would also help to buy and install a water shutoff valve from Home Depot to ENTIRELY stop the HOT water flow to the heater core. Conversely, when cold weather arrives keep the A/C compressor from operating altogether (but NEVER use recirculate) for improved FE. The standard RX has two c-best options for that specific purpose.

Sounds as if your brake light switch may have failed.

You cannot successfully upgrade from a "resonant" type knock sensor with the newer linear non-resonant type, absent changing the engine ECU also. Is it possible that the knock sensor is triggering because of low fuel pressure due to fuel filter or pump..??

The MAF/IAT module is located between the intake air filter and the throttle valve. The disconnect/reconnect will simply be recorded as an intermittent electrical connection, no harm, no foul. The engine control system will IMMEDIATELY return to normal operation and the CEL, TC & VSC diagnostic/failure indications will go out within a few drive cycles, and TC/VSC will resume functioning, provided the "incident" doesn't recur.

Just looked this matter up at techinfo.toyota.com The RX350 has a "VSC" pushbutton underneath the dash about where the driver's right knee might rest, between the gas pedal and the brake. PB is dual function, TC off, then a 3 second press will turn VSC off. The RX400h apparently does not have this feature.

There is MUCH confusion about TC and VSC. Some of the new Toyota and Lexus models have the ability to turn off TC via a pushbutton and then sequentually, ONLY sequentually, VSC can be turned off using the same button. TC, Traction Control, is designed to belay ANY level of wheelspin/slip resulting from the application of too much engine torque for the roadbed conditions. Most operate by quickly braking the driven wheels, sometimes only moderately, while simultaneously dethrottling the engine to prevent brake components form over-heating. Some RWD and R/AWD vehicles will delay the onset of engine dethrottling in order to give the driver time to react and feather the throttle as appropreate to regain traction. VSC is designed to activate only if over-stearing/plowing or under-stearing/skidding is detected. The problem arises, seemingly, more with TC than with VSC, if with VSC at all. Sometimes it is desireable to allow some level of wheelspin/slip due to engine torque to simply get up and moving initially, UNSTUCK. Rocking the vehicle back and forth to get out of a "hole" comes to mind. Toyota has just announced a new feature for their RWD and R/AWD vehicles, and that is a TC "sub-mode" wherein some minor level of wheelspin/slip is enabled before TC activates. My guess is that this sub-mode will never be added as a feature for FWD or F/AWD due to the safety hazards involved. Im not sure about this but I think that only F/AWD models have the ability to turn off TC and then VSC. There is a simple procedure for disabling TC and VSC on standard RX models which may also work for the HSD. Search for: wwest maf/iat disconnect

Yah, I got a question. How do you figure that chains on the back are SAFER! I mean, sure, you're overheating the VC and causing it to do its best to lock up, but how the heck do you plan on steering? First, during the winter months I always carry a second set for the front just in case of need. The answer to the safer question is in your owners manual: Higher traction on the front wheels vs the rear has a greater potential for leading to loss of directional control in adverse roadbed conditions. Just think of a tractor/trailer rig going downhill while braking to maintain a slow descent speed but with NO rear drag chains.

get the ECU relash that came out in April of 05. That is the only thing they offer. I personally found the reprogramming on my 02 ES was better than the original programming but still has some quirks. They are not going to offer you much more than that. Now if your ECU has already been reflashed make sure it was with most current verison. If memory serves correctly I think the TSB was number TC003-04R. The R stands for revised. The original TSB that come out in 2003/4 was not good at all. The revised programming was a major improvement, but not a total solution. i steviej Thanks! but I was reading alot of info on here and it seems like some people say that it made it worse?!?!?! is that just a chance that I am just going to have to take??? For the '08 MY Toyota/Lexus have come up with yet another solution, "FIX" for the transaxle design flaw. Search/Google for: wwest NCF hestation

I see an Acura RDX in my future, maybe... I was initially attracted to the RDX because upon reading about the SH-AWD system in detail, viewing the on line videos, etc, I decided it had to be the absolute best F/AWD system in existance today. F/AWD = Front torque biased AWD system, most with a sideways mounted engine or derived from a FWD "base". I currently have a 2001 AWD RX300. The RX's F/AWD system is just barely adequate provided you have an early one with a VC, Viscous Coupling, mounted across the center diff'l. The VC will, on rare occassion, help to provide increased torque to the rear drive line, as much as 75/25 F/R vs the normal ~95/5. As shipped the RX cannot have tire chains mounted on the rear wheels due to TOO TIGHT clearance between the tread and suspension. I added 1.5" wheel spacers all around so as to be able to use rear tire chains FIRST and ONLY, for reasons of safety. When the tire chains are fitted, rarely here on the Seattle eastside, the VC will tighten up the center diff'l a little quicker due to the F/R wheel circumference variation. An obvious additional plus from the spacers is a slightly wider stance and therefore more stability. So I test drove one of the early RDX's. I was impressed overall but didn't have a chance to really try out the SH-AWD system. Two other aspects of the RDX kept me from following up. A minor one was the seeming to me, CLUTTER, of the center dash instrument (non-tech)area. But a more important one was the fact that the turbo would come on line with even the slighest additional pressure on the gas pedal. I suspected that would result in rather poor gas mileage in comparison to my RX and as many of you now know that proved to be the case. Because of the turbo boost capability the RDX engine compression ratio is ~8:1. But that low 8:1 ratio results in a severe lack of early onset of torque until the turbo spools up. So, let's dream a bit, just a bit. Assume I have just won the lottery. I would immediately buy a new RDX and turn it over to a group of students at Western Washington State college with the following instructions/goals. Convert the engine to the Miller Cycle. Discard the turbo and instead use a lightweight low inerta carbon fiber positive displacement SuperCharger. The SC would be engine belt driven, primarily, but via a Toyota HSD type CVT/diff'l. The opposite input to the CVT/diff'l would be a 2-3HP synchronous AC motor, the motor itself driven by a variable frequency inverter such as Toyota uses for the various HSD drives including the Prius' A/C compressor. The engine would use a Porsche VarioCam-Plus intake valve lift system to vary the effective Miller Cycle compression ratio from 13:1 to ~8:1. 13:1 during idle or light load cruising, but as boost came on, rises, due to increased gas pedal depression or engine loading the compression ratio would rise linearly until at FULL BOOST the compression ratio would be ~8:1. There would be no need for a throttle plate, the VARIABLE SPEED positive displacement SC would provide the engine throttling functionality. Obviously there would be no turbo spool-up delay. Probably yeild more HP/Torque than stock plus STELLAR FE, so much so that a smaller engine might be more appropreate. Questions..??

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1) reseat the connections to the engine control ECU. 2) SOP, higher FM frequencies use a shorter antenna for increased reception. 3)...At initial engine startup the blower motor is programmed to not come on until the evaporator core temperature is low enough to provide at least some level of cooling for the incoming airstream. Other than that I don't know of any time the blower will be completely shut down. VERY low speed, QUIET speed, but not shut down. Oh, some of the later LS models would shut off the blower, or at least lower the speed significantly, if the captive cell phone rang or was in use. Maybe if the evaporator temperature rises back up to a higher temperature for some reason..??

Factory HIDs were not available for the RX until '01. So "standard" Sylvania Silverstars would provide the best night time forward vision. Not as impressive to oncoming drivers, drivers you will likely NEVER know or meet, as would be HID "colour" imitations, but possibly life-saving. LOST, am I. LS400 had HIDs as an option in '98. It is my understanding that the best HID "colour" insofar as aiding human eyesight is concerned is ~4300K.

Hmmmm...... I guess I haven't noticed that any new car with electronic engine controls and EFI, since about '92, has a fast idle mode.... Consistent ~800 RPM idle speed, yes, even with additional, intermittent, extra loads, A/C, power stearing use when parked, etc.

Randy, I'm afraid then that in the future you will be restricted to stick shift transmissions. With a stick shift you can push in the clutch pedal, downshift, release the clutch pedal, and then apply pressure to the gas pedal for GO..!! With an automatic the you only need to "learn" to apply pressure to the gas pedal.

Back in the 1950's when automatics were just beginning to be more common many them tended to hold the lower gear(s) a bit too long. Of course for many of those that arose out of the fact that only two gear ratios existed. So many of us learned that the transmission could be caused to upshift a bit sooner, softer and smoother shifting, than normal via a momentary "lift" of the gas pedal. "Back" to the future...??

Personally I'm holding out for an Lexus HSD AWD version of the RAV4, provided it uses the I4.

Google for: wwest DBW hesitation coastdown or: wwest NCF "gas pedal" Latest Toyota/Lexus models have new, additional. "learning" firmware within the engine/transmission controlling ECU that tries to judge/determine your near- future intentions when you let up on the gas pedal. QUICK/FULL "letup" = presumption of driver intention to coastdown to a lower speed, remain in current (low, lower..??) gear ratio. S.L..O...W..../partial "letup" = presumption that driver wishes to enter cruise mode, upshift the transmission if appropreate. This is, seemingly, Toyota/Lexus latest "FIX" for the design flaw incorporated back late in the last century via "abolition" of the ATF pressure accumulator to sustain fluid pressure during periods when the engine is, might be, at idle and a gear shift is required immediately following a previous gear change. That's why DBW was adopted as an earlier fix. DBW could be, was used, is STILL used, to delay the onset of engine rising torque when you depress the gas pedal and there is no fluid pressure reserve to provide the required downshift since the transmission has just completed, or is in the process of completing an upshift due to your "just" previous gas pedal "lift". I guess now with this NCF, New Car Feature, we need to "teach" our right foot how to best manage the gas pedal so as to not encounter a "double shift" instance and therefore a 1-2 second engine/transaxle-transmission downshift delay/hesitation.

My guess would be that the engine/transmission ECU firmware automatically switched the transmission into "snow" mode with the issue of potential degraded engine performance came about. Basically the same reason VSC/TC/BA are disabled with a CEL. Probably disabled the OD mode at the same time.

Wow, for once I agree with wwest! :o One should remember that all season tires were always a no cost option on all years of the LS400. The standard tires were summer-only tires. Although I used all season tires during much of the 18 years I have been driving LS400s, I am finding that my 2000 LS400 is much more enjoyable in the spring/summer/fall with summer only directional tires. I've been thinking of summer tires when it comes time to replace my all seasons. What kind of tread life have you experienced with them? And what about traction issues in colder weather? On the AWD RX300 the first set of turanazs lated almost 40,000 miles. I don't remember the numbers on the LS400 other than the mileage was acceptable. I run on turanzas all year around, ever wintertime trips in the RX to central MT, but am QUICK to install chains when the need arises.

Torque stear was NOT a consideration, not at all, in any of my statements regarding the safety hazards of driving a FWD or F/AWD vehicle on a low traction, ice, packed snow, surface. Besides which, on a slippery roadbed surface torque stear would have little or no opportunity to exhibit. Best to compare the FWD or F/AWD safety issue to leaving the diff'l lock engaged with a 4WD/4X4 vehicle once "underway", NOT SAFE.

And with any luck at all you'll never have anyone sue you for hitting you headon due to poor visibility at or near dusk, just before sunrise or on a dark cloudy day. If you feel you MUST be in control then wire the DRLs into the street/parking/tail lamps for FULL protection. I would think that most people are able to remember to turn their lights on when it starts to get dark. DRLs make you look like some loser that forgot to turn his lights off in broad daylight, or that you turned you lights on instead of your blinker. There is absolutely no data that indicates DRLs decrease the possibility of an accident. Besides, if someone hits YOU "headon", it's them that will get sued. "...it's them that will get sued.... Only provided someone in your car survives.

No, not at all, I'm a bit like that myself, except being somewhat of a perfectionist I want everything to be fully FUNCTIONAL. So my fog light circuits, LS & RX, have been modified so the fog lights can only be used alone. Well, along with the street/marker/parking/tail lights that is.

Your 911 motor has about 4X the amount of oil in it than the RX350 motor. That goes a long way to explaining the extended drain intervals. My '01 AWD RX300 takes 5.3 qts for an oil change, the 911 requires 12 qts. Doesn't the factory recommend 7500 miles between oil changes for the newer RX...??