jaswood

But it would go "flat" were you to set and listen to the radio with the HSD not "started". This way no one cares if you fully deplete the 12 volt battery.

For whatever reason the dealers are reluctant to show you the FULL c-best listing. The want you want to see will have the capability of disabling the A/C indefinitely, throughout multiple engien starts, until you depress the A/C PB to re-enable it. There is a second one that will unlink the A/C from automatically operating, with an indicator, in defrost/defog/demist mode, or even partial windshield airflow mode.

Was that a typo or was backwards intentionally...? Don't ALL modern day systems switch AUTOMATICALLY to FRESH when you activate defrost/defog/demist, or even partial windshield flow...?

The industry thinking, WRONG thinking, is that as long as the A/C is operational then it will have enough dehumidification capability to keep the cabin Rh within "safe" bounds insofar as windshield fogging is concerned. The problem often results shortly after the A/C compressor is turned off, disabled for some reason and now the mositure previously condensed onto the evaporator vane/fin area will be released into the cabin. The A/C compressor is disabled with the OAT below ~35F, or if you drive into such an area. Other than the above condition unless you have the dealer set the c-best option otherwise the A/C will ALWAYS operate, often without an indication, in deforst/defog/demist mode. So, yes, with many modern day cliamte control systems as long as the A/C is operational the system will remain in the selected, recirculate, mode. But beware of/if the compressor should be shut down for ANY reason, driving into a colder area, for instance.

With the gas pedal fully released the engine ECU attempts to maintain the RPM at ~800 RPM. The only thing I can think of that might over-ride that "mandate" would be the need to keep the A/F mixture within the correct range in accordance with the A/F mixture control oxygen sensors. You have a vacuum leak somewhere. Don't overlook the PS vacuum line.

And Toyota says there is no software bug that could result in SUA.... Sure.

Turning off the "auto-recirculate" isn't the problem. The "auto-recirculate" is the function that automatically puts the system in "re-circulate" mode when you first start the engine and the cabin temperature is eleviated...typical summertime day. Even in a "normal" car (non-NipponDenso, Denso US) climate control design, it can be hazardous to use re-circulate mode for an extended period on a coolish, or cold, day. NipponDenso designed systems have a rather serious design flaw pertaining to this very same operational area. Those designs are even more prone to suddenly turn hazardous, quickly fog over the interior windshield surface, on a coolish or cold day. The base problem is that in recirculate mode any moisture somehow trapped within the cabin, wet coat, wet folded umbrella, might raise the cabin Rh high enough that windshield fogging results. To help alleviate that possibility ALL modern day vehicles will remove re-circulate mode within about 2 minutes in order to FLUSH the cabin of stale/humid atmosphere. A note of CAUTION...! Should you by chance find yourself with a windshield that begins to fog over while underway, or even actually suddenly FULLY fogs over, simply switching the system to defrost/defog/demist will not suffice. You MUST also simultaneously turn the HEAT up to MAXIMUM in order to most quickly remove the condensation and/or reverse the trend. Because of the flaw in the design it is best to disable the A/C throughout the period wherein cooling is not needed/desired. Lexus has a C-best option, 2 actually, that will allow you to disable the A/C indefinitely, even in defog mode, until you wish to use it for actual cooling.

What did you do with the oxygen sensors mounted downstream of the cats, open circuit or left connected ???. Leaving them connected, and exposed to atmospheric oxygen levels the idle and low engine loading mixture would probably run extremely RICH. Leave them disconnected....GUESS.

Most likely a plugged up cat. Internal honeycomb structure fails and chunks block higher level exhaust flow.

Other than a metallic screen there is no filter in the early RX transaxles. After much ado I was advised that I should keep watch on the ATF condition at each and every engine oil/filter change. My '01 had the ATF drain and refill, 5 qts, twice, only weeks apart, at ~40,000 miles before the ATF looked satisfactory. The same procedure was done, DIY, at ~90,000 miles. ATF in good condition is red/pinkish and transparent. Mine also smelled burned before the drain and fill. The burned ATF is the result of the design flaw not the base causative factor. On the other hand if you leave the burned ATF in the transaxle it will undoubtedly accelerate the failure.

Where did you take your automotive apprenticeship, at the Bermuda Triangle Vocational School? No, school of hard knocks, or as my mother used to say, "self schooling is the best you can get" Started with Deere, Farmall, AC, Ford tractors back in the mid-fifties. Mostly Ford cars/trucks for mid-term. Graduated to Porsche 911's, LS400's and RX's starting in the early 90's. Did have one GS300 MY2000 but didn't keep it very long.

Inside that "relay" is a current flow sensing resistor so the ECU can monitor if the high mount brake light bulb draws current when the brake is used. If the OEM bulb was shorted for a long period of use then the resistor link might have been burned open. Due to the design of the "relay" circuit normal voltages would be present except with the bulb load in place. Just to be sure...the "relay" I refer to is mounted just behind the driver side rear wheel on the inside of the cover on which the 12 volt alternate plug is mounted.

Inside that "relay" is a current flow sensing resistor so the ECU can monitor if the high mount brake light bulb draws current when the brake is used. If the OEM bulb was shorted for a long period of use then the resistor link might have been burned open. Due to the design of the "relay" circuit normal voltages would be present except with the bulb load in place.

If the bouncing rate increases with road speed then you have failed/failing driveshaft needle bearings.

Can't say for sure about your '94 but for the '95 LS400 there was/is a TSB involving rerouting the wiring harness near a connector on the steering column. Too much sideways stress on the connections without the rerouting. You can access the TSB via a daily subscription to techinfo.toyota.com.

he just put a new battery in it, it is now time for new solenoid contacts No. The solenoid is initially, instantly engaging the starter motor and that additional HUGE current load is resulting in the 12 volt supply voltage dropping to below the voltage required to keep the solenoid engaged, the starter motor load is removed, the 12 volt supply "recovers" to the point that the solenoid engages again.....repeat the sequence...rapid click-click-click. Had the battery not have already been changed the first thing I would recomment is a cleaning and burnishing of the battery posts and connections. On the other hand did whoever replaced the battery do that...? Anew battery being defective is not unheard of.

See the "other" post.

NO, the 12 volt battery SYSTEM is used to power the 12 volt accessories. Once you "energize" the HSD system the HV battery will be used to provide ALL loads requiring a 12 volt source. The only real reason, cause, for the 12 volt battery is to sustain all of the ECU "learned" parameters, the clock, and the radio settings during periods of non-HSD operation. Absent the above volatile R/W memory "keep-alive" voltage requirement, months long requirement, there would be no need for a 12 volt battery at all.

Only the dome light just behind the front seat comes on. I replaced mine with a Ford Map/Dome/Curtesy light. Wired it so all three bulbs illuminate with an open door. Helpful aspect is that left and right map light bulb fully illuminate the front seats and the floorboard/dash area forward of the front seats. Also, the front passenger can use, individually, the new map light without interferring so much with the driver's night vision. If you wish you can easily wire the front light in parallel with the rear dome and have both come on with a door opening. You can also wire the front light switch such that it only turns on the passnger's new rear, over-the-shoulder, map light.

Rapid clicking noise/sound is the result of getting 12 volts to the starter solenoid prior to starter commutation engagement and then voltage drops due to the additional, HEAVY, starter current load. Most commonly caused by a weak battery, but otherwise by a "high" resistance (~>100 millohms) connection between the positive or negative side of the battery and the starter + or - sides. A 12 volt battery with a "dead" cell can still be "fully" charged, 12.5 volts, but the terminal voltage will drop the instant a more serious load level, >100A, is applied.

"...Oil covering it..." ATF, Automatic Transmission Fluid, should be pinkish. I am given to understand that there is KNOWN method for blowing the rear crankshaft seal and that is sometimes done by service personal in order to sell a $1200.00 job. What about forward of the transmission pan..? I have seen what you describe resulting from PS pump leakage, steering rack leakage, and even valve cover gasket leakage. It is not all unusual to have to retighten the sump bolts sometime after (months) installing a new "gasket".

"...since the one on the 400h was woefully inadequate..." Why, how so....? I don't know the answer for certain but given the level of technological advancements in the 450h vs the 400h my guess would be that a smaller, lighter weight, 12 volt battery might be used in the 450h vs the 400h. That might, or might not, mean a lower CCA capacity in the 450h. You have a method, provided the HV battery SOC is not also fully depleted, for restoring the charge of the 12 volt battery should it become somehow depleted.

Except the 12 volt battery is powering the stereo and all the other things that run on 12 volts - headlights too. Would a diode and a few capacitors be able to keep the headlights on? The ideal design for the 12 volt battery and 12 volt battery charging system will be that NO POWER is drawn from the 12 volt battery during operation of the HSD system. The design would be such that once the 12 volt battery SOC is depleted during the starting process it will be fully recharged ASAP and that full charge will be maintained throughout the full period of HSD operation. As you know, should the HV battery SOC become too low due to the "bleed" into the 12 volt supply load then the system will simply restart the ICE in order to restore the HV battery SOC. There might be a slight voltage "top-off", different voltage charge maintainance level, 13.2 volts vs 13.5 volts, when the ICE isn't operating vs not. But never enough difference in SOC to take a chance on not having enough charge for the next "start" even after a decently long period of storage. This is unlike a more standard battery/alternator charge system wherein due to engine RPM and extreme load levels the alternator may not have enough "juice" for periods of time. Even so, by system design, the 12 volt battery will NOT be, CAN NOT be, on the average, the source of power supplied to the 12 volt system loads.

Sorry Craig didnt see the post, no interesting story that I remeber of, I think I was just starting the car in the morning come to think of it ...I broke my axle bolts on my porsche from accelrating too hard, does that count as an interesting story, had it on cruise at 145MPH :whistles: Sorry Bro, just cranked the car in the morning and it sounded like the starter went out. Traveling at 145 MPH there is NO Porsche that can produce enough torque for acceleration to break axle bolts... Perhaps you didn't mean simultaneously...? Or you downshifted TOO FAR...?

Billy would be overwelmed by the technology in the 2000 LS. ;) "VSC? We don't need no stinking VSC!" I already am overwelmed...... and what is VSC? (I know I shouldnt ask) VSC is something you alsolutely DO NOT need..... Except.... For the one time (few times??) it activates and saves your life.