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Lexus LS 400/LS 430



  • Thank you for your information. I registered in lexus driver website and downloaded the manual. The I/O button is not standard lexus button as shown in the manual.
    It has the same looks as the picture link : display-unlock-bluetooth-unlock-and-nav-destination-input-while-driving-remove-1- 0.jpg

    I found the picture from lexus club forum h-unlock-and-nav-destination-input-while-driving.html

    I have no clue what the button is about. Maybe someone did the same thing as the forum post. Why did someone unlock the bluetooth/nav ? What is the purpose ?
  • vchengvcheng Posts: 1,284
    ... aftermarket modification is done by some to interrupt the VSS input to the navigation/bluetooth system to enable some of the locked out features while the vehicle is moving.
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaPosts: 57,595
    Ah....a HACK! Now it makes sense. So it allows you to program while driving?

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  • vchengvcheng Posts: 1,284
    Normally, the navigation system locks out the ability to program a destination if the vehicle is moving. When the vehicle speed signal is interrupted, it thinks the vehicle has stopped and thus a person can program in a new destination.

    Of course, when the signal is restored, the navigation system has to update its new location, leading to a jump in location. Some versions of the software occasionally have problems, but mostly it is able to deal with the conflicting location information.
  • acco20acco20 Posts: 211
    mike, would you please list the actual lexus site that you visited to download the manual? I would like to do that also. Thank you.
  • wwestwwest Posts: 10,706
    On-board diagnostic code 41. Supposed to be an indication that some fault that was recorded was intermittent and/or has now been fixed. Dealer service manager said he reset the code but it came right back...???

    Tricky sequence to reset myself so I haven't been successful.

    Does anyone know if the airbag will still trigger with only this code..??
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaPosts: 57,595
    Code 41 is set whenever there has been a diagnostic code in the airbag system. If the proper code clearing procedure has not been met, Code 41 will always be displayed. It is possible that Code 41 is displayed as a result of a center airbag sensor malfunction.

    * After repair of the trouble areas, the diagnostic code retained in the ECU memory must be cleared out by removing the EFI fuse (2OA) from J/B No. 2 for 10 seconds or more, with the ignition switch OFF.

    HINT: Cancellation can also be done by removing the battery negative (-) terminal, but other memory systems (clock, etc.) will also be cancelled out.

    * If it is necessary to work on engine components requiring removal of the battery terminal, a check must first be made to see if a diagnostic code has been recorded.
    * After cancellation, road test the vehicle to check that a normal code is now read on the "CHECK" engine warning light.
    * If the same diagnostic code appears, it indicates that the trouble area has not been repaired thoroughly.

    NOTE: code 41 appears in a number of different systems of the car, not just airbag system. So the tech has to be in the right system. "41" can also mean deffects in ABS or Height Control.

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  • wwestwwest Posts: 10,706
    I was running the onboard diagnostic and the airbag light "blinked" 41.

    I had switched out the instrument panel and apparently the air bag system had detected an open indicator bulb.

    Finally cleared the fault by ignoring the shop manual instruction insofar as timing sequence. Says 1.0 seconds +0.5 seconds in each position when what really worked was less than 0.5 seconds.
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaPosts: 57,595
    Yes I've often found that some of these reset instructions are a bit lame. Anyway, let's keep our fingers crossed. :shades:

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  • First, Lately my '95 LS 400 has been stalling out on me as I pull off of freeways, decelerating. First happened days after I had gotten my oil changed at Oil Changers and they had replaced PCV valve and had me restart the car before they had put valve back. Ooops! Don't know if that's related, but it didn't used to do it. Never does it in around town driving, only when I've been on freeway, so I'm wondering if has to do with something heating up? Always starts back up, immediately. Any ideas?

    Second, when I was researching buying the car, the only "drawback" I read was it didn't handle that well in wintry conditions. Got first hand experience of that yesterday, when I spun it out on I-5, Siskiyou Summitt in Oregon, in very light snow at 60 mph. Hair ball stuff. Rear end slid out on me, and then I'm doing a 540 in the middle of the freeway. I remember thinking, damn I'm surprised the car didn't roll (such was the force of the spin) which I guess speaks to the "good" handling of the car, which I've also been told about.
    Any tire suggestions? Studded snow tires? (they're legal here in Oregon). I've got some Cooper all-weather on my rear tires, but they didn't do me much good yesterday, unless I should have them on front, too, to keep things "balanced".

    thanks for any suggestions on either of these items.
  • wwestwwest Posts: 10,706
    Nothing, absolutely NOTHING, beats being well aware of roadbed conditions, even POTENTIAL roadbed conditions, and driving accordingly. I like to hope you didn't have CC enabled but it sure sounds so.
  • CC = Cruise Control???
  • wwestwwest Posts: 10,706
    '92 LS400, 160,000 miles, has been slowly losing coolant.

    Finally found a crack in the coolant reservoir near the coolant level sensor. I assume that normally the coolant never rises high enough to leak out this crack...but...

    Is it possible that because with the crack the system cannot be pressurized and the coolant is boiling off..??
  • vchengvcheng Posts: 1,284
    What is the rate of coolant loss? Are there any other issues, like white smoke or a sweet smell to the exhaust?
  • wwestwwest Posts: 10,706
    No signs of steam/vapor from the exhaust even with a HARD coastdown, extreme intake manifold vacuum, in 1st gear. No smell of anti-freeze except when expansion tank was overfilled and seepage from the crack result in odor.

    If the system can't be pressurzed will the coolant actually
  • vchengvcheng Posts: 1,284
    wwest: If the system can't be pressurzed will the coolant actually

    The short answer is yes. Pressurization is used to elevate the boiling point of the coolant, and a return to atmospheric pressure due to a cracked reservoir or failed radiator cap will reduce it. This can lead to a slow loss of volume of coolant. It will also reduce the total heat transfer capacity of the system from the block to the radiator and under severe service conditions can lead to overheating as well.

    PS: More details here:

    and here: - ater-And-Solutions.html
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaPosts: 57,595
    Is there a pressure cap on your reservoir?

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  • vchengvcheng Posts: 1,284
    On an LS, I think no, but some other makes do have pressurized reservoirs.

    I do not know about Toyota Red/Pink formulations, but a glycol based coolant will have an accelerated evaporative loss if there is a crack in an unpressurized reservoir.

    Hence I go back to my original question to wwest: What is the volume of the loss?
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaPosts: 57,595
    German cars generally have pressurized reservoirs, yes.

    Maybe the car is just overheating?

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  • wwestwwest Posts: 10,706
    The expansion tank cap is rated at 17lbs.

    I sealed the crack with epoxy and if it holds we will see...

    The engine coolant temperature gage is rock solid at 2.3 marks and has been since the beginning.

    Maybe a pint within a week but the car isn't driven often enough to really say.
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaPosts: 57,595
    Also (gulp) check your automatic transmission for coolant intrusion.

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  • wwestwwest Posts: 10,706
    Hadn't thought of that...

    Via the ATF cooler inside the radiator...??
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaPosts: 57,595
    Yeah, a long shot and a dreadful situation but hey, it only takes a minute to check. If you see "pink and frothy" like a strawberry milkshake, you're in deep doo-doo.

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  • wwestwwest Posts: 10,706
    Just pink...thankfully.
  • wwestwwest Posts: 10,706
    The coolant reservoir holds at 20PSI for longer than I was willing to wait.

    ATF looks clear pink.

    Engine oil looks normal.

    Car parked in leaks on floor.

    Lost ~8 ounces, 10 miles to, hour dinner, 10 miles from. Tank was at 10PSI of its own accord when we arrived at the restaurant.

    No obvious "smoke"/steam/vapor at startup or with low gear coast down, DRAMATIC coastdown, high intake vacuum.

    One other anomally..

    At ~40MPH and 1500RPM the car "tugs"(***) once in awhile. Turn off the OD and drive 40MPH, or drive at 1500RPM no "tugs". 45MPH in OD no noticeable "tugs".

    OD lockup clutch slipping...due to line pressure being too low..??

    *** Feels as if something pulling backwards just momentarily. First thought it was an engine miss.

    Engine RPM remains constant but that may be meaningless since the ECU drives it not engine directly.

    Ran the car in diagnostic test mode several times with no resulting codes.
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaPosts: 57,595
    Well, leaking or other possibility under the laws of physics as we currently understand them. :P

    You aren't drinking this stuff are you?

    I think you need to pressurize the system with a pump, about 3-5 lbs above cap pressure (no more) . Get under, look for leaks...if none....then pull spark plugs one by one (while still under pressure) and look for coolant on the tips.


    (Don't forget to set your clock ahead one year before you go to sleep!).

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  • wwestwwest Posts: 10,706
    I removed the fill cap and installed a rubber plug with a valve stem epoxied in place. System held 20PSI for more than an hour. I'm becoming very much afraid that I have a head gasket leak....

    But strange that no vapor out the tail pipe.
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaPosts: 57,595
    The head gasket doesn't have to leak into the combustion chamber per se. It can leak to the outside, or to the oil galleys. Besides, in cold weather this vapor would be hard to spot above and beyond normal water vapor you see at this time of year.

    The pressurization test should reveal all, especially if you can get up on a lift. If you see no drips under pressure, then it's time to start pulling spark plugs.

    Leaks can be tricky--they can travel along the length of the engine, they can get burned up by exhaust, etc.

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  • wwestwwest Posts: 10,706
    The problem that the 20PSI does not show signs of leaking down in under an hour.

    Leaving me with the thought that I have a slight head gasket leak. Head gasket leaks can allow combustion pressure into the coolant system or coolant into the cylinders when there is a high vacuum there.

    I see no signs of combustion pressure and the HARD coastdown in low gear doesn.t produce ANY "white" smoke.
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