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Lexus LS: Problems & Solutions



  • q45manq45man Posts: 416
    And clean out all the PCV and EGR crud that is inside your intake behind the throttle body.
    TPS wear [bad spot/failure] very common after years.
  • paul29paul29 Posts: 178
    Check for diagnostic codes , the temp sensor could be indicating cold engine in error. The idle speed is controled by an isc device which raises the idle for various situations , this device may need cleaning or replacing . The power steering pump has an idle up device which raises engine speed when demands are made on the pump , this prevents slow idle or stalling. It does this by bypassing air around the throttle plate , this can be checked by pinching the hose to the intake manifold , preventing the bypass and resulting idle up , if the device is defective . Many things can raise the idle on this car if there are defects including a/c , rear defrost , etc and also as noted in the above posts. Happy hunting .
  • kl3415kl3415 Posts: 12
    Paul29, it's strange you mentioned the power steering pump. I recently had that changed. However, I had to take it back 3 times because it kept using fluid through my exhaust manifold. My mechanic finally solved the consumption problem by changing some type of pressure switch. A few days later this idle problem occurred. I changed the TPS last night, it helped some but there still is something wrong. Any suggestions?
  • paul29paul29 Posts: 178
    Check to see that the two air lines are actually attached to the p/s pump idle up valve and the intake manifold and throttle body respectively . There are two hose fittings directly off the front of the intake manifold above the idle speed control valve , the one on the drivers side , with the hose going towards the pass side is the p/s idle up line , if the valve is stuck open or bypassed and you have a high idle condition you would pinch this line to confirm . What is your high idle rpm ?
  • kl3415kl3415 Posts: 12

    my tach indicates 900 in park, and slightly lower in drive or reverse. Now I've noticed, after chaning TPS, once I reach approximately 60mph my tach suddenly drops from about 1100 to 900 and my car slows down accordingly. I have to increase acelleration to get back up to speed. My mechanic has the car now and I hope he can get it back to specs soon. I will pass your advice to him. Thanks again.
  • paul29paul29 Posts: 178
    With A/C on 900 rpm is normal , about 600 rpm with auto climate control sw.and /or A/C sw off. There is a revised tps available from Toyota for the early LS 400 P/N 894520-22090 which addresses the condition you observed. Would this be the one you used ? Also there is a specified procedure for adjusting the TPS . this must be followed when replacing it . Good luck
  • lando2lando2 Posts: 12
    I am interested in what the operational life of an LS 400 would be?

    I saw one for sale (St. Louis area) for $6000 w/ 190000+ miles on it. Is it worth the trouble?
    The vehicle itself is in fine condition (cloth int, black paint, sunroof).

    I am curious to know, so any commentary is appreiciated.
  • wwestwwest Posts: 10,706
    1978-83 POrsche 911 SC often go for as much as 250k without any major mechanical problems. LS400 came out in 89, lots of things have improved since the SC.

    IF the appearance, exterier and interior, is good I would go for it and expect another 50k or so easily
  • q45manq45man Posts: 416
    We have clients with 300,000 miles on 1990 LS400, I have 245,100 miles on my 90 Q45 and we have a company Q with over 400,000 miles [obviously things have been replaced].

    With proper EXTRA maint [oil and fluid changes] these precision engines can last a long time.

    We have never had to change a tranny on an LS400 but they use Special Toyota Synthetic ATF and get a pan drain [partial replacement every 2 years or 30k].
  • gee35coupegee35coupe Posts: 3,475
    I just bought it. Runs great. How much should I expect to pay for a valve cover gasket? And should I go ahead and have a major tune up done at the same time?

    Also the telescoping feature isn't working. What worse case scenario in cost to fix it? Other than those two issues it's a great car.
  • My traction control off light stays on. How do I get the traction control to work. Is there a button for it.
  • I just purchased an 91' lexus 400 from an auction.

    that's a grand total of $3,120

    $2165 - for car
    $65 - for key
    $50 - electric problem
    $700 - rear door replaced, trunk, back light(the one with the trunk key), paint. the car still needs minor body work and possibly a paint job.
    $70 - to tow it out the lot
    $70 - trunk lock
    $35 - oil change

    1)It seems that the power steering pump is leaking
    2)I have the infamous leaking LCD climate control
    3)It has a ticking noise in the engine. (does any one have this problem)
  • q45manq45man Posts: 416
    I'm sure you'll find other problems!
    PS steering pump and res common problem -replace. Rack and boots?
    LCD replace!
    The valve shims [they come in 50 sizes] need replacing to adjust for valve train wear!

    Another $3,000 ought to get everything functioning, but you seem good with junk yards so less.
    How is AC and all the suspension? Shocks probably shot!
  • the rack and boots seem fine. the car drives like a dream and no noises come from it when I have the window down.

    Can it be that the car is so well made that rack and boots and even the suspension can be bad and I can't tell?

    It seems the car was parked at the auction from 05/01/02 without ever being started. can that be the cause of the ticking noise or do you think the previous owner negleted the car.
    How much for the valve shims as a seperate job?

    The ac works perfectly.

    the next question i have is

    I'm currently waiting for the paper work to come back from motor vehicle, i'm afraid to start the car because the power steering fluid can leak into the alternater (which I had checked two days ago and they said it was in excellent shape). Can the power steering fluid leak into the car with the engine not running or does it need a vacuum from the engine to push the fluid?
  • hieutdohieutdo Posts: 2
    I have a 1990 LS400 which started to have problems. The "Traction Off" and "Engine" symbols illuminate and remain on the dash board. I was able to turn off these sysmbols by disconnecting and reconnecting the battery, but the problems still show up again after a short drive. I followed the suggestion to locate the fault code by connecting the E1 and Tc terminals and counting the number of "Trac" light flashes between the pause. The pattern is 51. I only have the second volume of the service manual and could not interpret the fault code. Could somebody please help me to look it up.

    Many thanks,
  • paul29paul29 Posts: 178
    You need to get the code/s from the engine diagnostics , this has turned on both lights . Turn the ignition on and connect TE1 and E1 , read the code/s from the " CHECK" engine light. Could be as simple as an oxygen sensor heater.
  • pj2323pj2323 Posts: 43
    my 1992 ls400 " door open light" in the instrument cluster has stopped working. it will not work with any of the doors open. does anyone know if this could be a bulb, or possibly a switch?
  • q45manq45man Posts: 416
    Riding ok to someone who never drove it new is one thing.......the LS400 to new specs is another.
    All the rubber bushings in suspension arms/sway bars, tension rods etc shock boots/bumper stops spring seats should be examined for wear and rubber turning hard also exhaust hangers, transmisson and motor mounts.

    Lots depends on location: heat, road salt, potholes.......Atlanta/South is pretty benign except for heat.

    Purchase both shop manuals and have fun making it near new.
  • New here. Looking for some input. Saw a 91 LS400 in immaculate shape on the exterior and interior, engine compartment and underneath. Came home to check out the message boards. Not sure if it is equipped w/trac control or heated seats or air susp. Has the premium sound though. Asking price 7,000. Has 132,000 miles.

    If car checks out w/mechanic is it worth the price? What should I look for when I return to test drive? What are the possible pitfalls with this mileage?

    I spent 10 minutes just looking it over, It really is in good shape visually with chrome wheels and excellent tires and high shine to the paint. Car looks like it has been kept in a garage. However without the key I was not able to start it up and check any electronics, motor noise or AC.

    Is "cold air" the only check for the AC system or is there something else I can look at when I return?

    I'm getting rid of our third minivan and finally getting my wife and I a luxury car. Will this fit the bill?

    Thanks for any responses.
    Joe .....
  • kstittkstitt Posts: 9

    I have a 1991 LS 400 with 197,000 miles. I've taken care of it and plan to hold on to it for several more years. I'll tell you about the repairs I've had in the last four years between 150,000 and 197,000 miles. I replaced the air conditioning compressor at 150,000, the power steering pump at 175,000 (also at 80,000)and the rack and pinion at 196,000. The LCD for the a/c temp display is short, but I haven't replaced it. I replaced shocks at 110,000. I think these are common problems. I would also look at the alternator. Check the service records. If these items haven't been replaced, I would think it likely that you would be faced with one or more of these which range between $800 and $1,300. It's a great car, but the replacement of these items is no small matter (but it still beats a large loan payment!)

  • q45manq45man Posts: 416
    Almost every used 90-93 LS400 [and q45] we see for a prebuy inspection needs $3,000 worth of work to return all systems to 100% functioning.

    Why else would it have been sold!

    Cold air [feel] is not a useful measurement need to measure the temperature at vents after 15 minutes of driving in 90F ambient..........after all you can be fooled by a quicky recharge which leaks out after a week.
  • gee35coupegee35coupe Posts: 3,475
    I've been driving my 1994 LS for 2 years now on nothing but a tranny flush. Looks like when I get my GS out of the T3 on S. Cobb I'd better bring in the LS. I need to get the power steering pump checked to make sure I don't get the alternator problem. Prolly needs a T-belt too.
  • Thanks for the input guys. I bought it. Now the funny thing. Lexus dealer showed a miss. Needs plugs, wires, rotor: 735.00. Brakes 65%/59%. No other reapirs needed at this time.

    Service records showed maint every 5,000 miles like clockwork since 75,000. Even had service @ 120,000 and 130,000 (just 2k ago). Up to 75,000 miles the car had service every 7,500 miles (probably the first owner). Service rep was impressed.

    Here is the funny thing. I drove the car 45 miles over two days before the dealer checked it. Then after the check, the car DID have a miss. In fact we never left the dealer lot and questioned them.

    They said the miss was there. I never felt it on my test drive till AFTER the checkout. We checked and a full tune up was done at 120,000, just 12k ago, w/plugs and wires.

    After discussions with mechanic, salesman, service rep, we came to the conclusion the engine cleaning done by the seller had caused a problem.

    We drove off, by the time we got down the block, the miss was gone and it drove fine for 8 more miles back to the dealer. After negotiating and a calculated gamble I decided to buy it (at the right price) figuring any moisture would be gone and the miss may not come back.

    Well it came back and is very intermittent at idle. You can see quick a notch on the tach when it happens. The needle moves (drops) about the witdh of the needle and returns. It is very quick, but you can feel it. Sometimes it wil happen 3 04 four times in a row, then stop. I can't get it to happen above 1100 rpm. No pattern on when it happens. But does it about 10 - 15% of the time at a stop.

    Runs fine and very smooth with plenty of power otherwise.

    Any thoughts on the low idle miss? Can't believe new plugs and wires are the cause after a engine wash. I would think it would not be intermittent if it was plugs.

    Good news: Suspension in front has been worked, ps pump sealed at 80k. Temp display is bright as is radio display. Stereo is awesome. Both major tune ups have been done and belt done.

    No A/c work has been done. But it is cold.

    Thanks ago for your input.
  • jeffmust2jeffmust2 Posts: 811 could just be Bad Gas, water in the gas, etc. Not unusual if the vehicle has been sitting outside for a while. You could try pouring some isopropol alcohol into the fuel tank to dry up any water that might be in there.

    I had a '95 LS and have a '98 LS now - great cars; enjoy!
  • gee35coupegee35coupe Posts: 3,475
    The plugs may be a bit fouled. Give it a while to burn of any deposits it may have. My GS did the same thing for a while. It's fine now.
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaPosts: 57,815
    Sounds like possibly a bad injector spray pattern.

    If the plugs were causing a low speed miss, it would be much worse as the car got underway I think.

    This is a think fuel related not spark related.

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  • Jeff, Gee and Shift,

    Gas related, that's a good take. Filled up and drove to San Diego and back. Didn't notice it. Going to note mpg, as that will be a good indicator.

    Thanks for the input.
    Joe ...

    It cruised like a cloud .....
  • cmotomncmotomn Posts: 2
    Q45, I'm trying to decide whether or not I should change the timing belt for the first time on my 1995 LS400 with 144K miles. Are all LS400 4.0L engines from 1990 to 2000 "Non-Interference"? I've heard a rumor that 90-94 engines are non-interference, but that 95-00 engines are not because of the higher compression ratio. Do you know the answer? I want to avoid causing damage to my engine if the timing belt breaks. Thanks in advance!!!
  • jeffmust2jeffmust2 Posts: 811
    for a listing of interference and/or non-interference engines:

    Shows all LS400s, from 1990-2000, are non-interference.

    Also shows the recommended change interval for LS timing belts:

    1990-1994 60k miles
    1995-1997 90k
    1998-2000 90k

    At 144k without a change you probably won't cause much damage if it shreds - but you sure will need a tow.
  • wwestwwest Posts: 10,706
    Why does my 92 LS show 90k for timing belt?
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