XL2007

Thanks for the PDF diagram. I didn't see anything visually wrong with the trunk wiring, so that's been ruled out. I noticed that leaving the battery disconnected for more than thirty minutes will slowly reset not only the TRAC, but also the idle situation. A day after disconnecting the battery, the idle returned to normal, then edged up to a high 750-800rpm in Drive, and 1000rpm in Park/Neutral. It stayed like this for a couple of days, until I needed to turn on the heater (cold snap :D ). I'm not sure if that's related or not, but the idle slowly fell until it hit 250-300rpm. When I got back in the driveway, it just died out. I saw other posts pointing to the ECU as a possible culprit, among other things. What I will do is find another Throttle Positioning Sensor from another LS400 with TRAC and see if the symptoms continue.

This is the problem I'm having out of my 92 LS400. At first the problem seemed to go away with by replacing a bad battery, but it came back days later. The alternator was ruled out as a problem area. I don't have white smoke on startup, ruling out the PS leak problem, but the car simply either refuses to idle or will idle at 300-400 rpm, then die out after a few minutes. As for the idle air control valve everyone keeps talking about, I have no idea where that is and the picture guides people keep sending me are either for the wrong car or just don't point to anything.

Glad you found the solution to your problem. This was an interesting read! :) It's not over. I ran to the grocery store last night. On the way back, all of the symptoms came back -- the refusal to idle, and the super low (350-400rpm) idle on the off-chance that it does. I'll get a new TPS AND check the trunk lid wiring. If that doesn't help, I'm just gonna send the darned thing to the shop so it gets sorted out (even though that'll cost $$$$$ ).

Turns out a bad battery was the culprit. So I had it replaced under warranty and everything's pretty much back to normal.

HERE'S A BIT OF AN UPDATE: So I got back to messing around with the car, making sure that I've looked over everything else before tackling the IACV. So I rechecked and readjusted the TPS and check the throttle cables and other little bits. At this point, the car hasn't moved beyond 15 feet since the problem arose, so I decided to take it around the block once traffic cleared up enough. Two-footed driving came in handy :/ I get back in the driveway and put it back in park.........and it now IDLES. Problem is, it's idling at about 350 rpm and getting lower as time lapses. So I go back and readjust the TPS, only for the car to give out, again. I get back in and start it up..... .....and the battery's stone dead. I get it jumped off (which apparently didn't take much) and restart the car. It fires up beautifully and holds an idle at about 650-700 rpm. The next day, the car was a bit sluggish firing up. Apparently the alternator's charging it just fine, as I haven't had that problem again, just when it sits up overnight. At some point, I'll take the battery to an auto place to have checked out...or if I need a replacement. Pretty weird how the initial problem ended up "going away" like that. I might have to look into that trunk wire ground situation as highlighted in a few other threads, just in case.

I forgot to add that I found what apparently looks like TWO TPS sensors on the throttle body. Maybe because it's a TRAC model, but it looked plenty different than the pictorial guides I have. Now TRAC (which hasn't been working previously) stays on consistently. I've been out of town this week and hadn't been able to work on the car as much as I wanted to. I'm going to double-check the TPS, just on a hunch, perhaps even get a new one and see how that works. I don't see any blue smoke or anything else that might indicate a PS fluid leak or the IACV sucking in said fluid.

I managed to clean the throttle body today. And man, was it just gunked up! But it still didn't fix the problem. Also, the TPS seems to be in good order, as I can adjust the idle revs....when I'm holding the throttle cable so that the car doesn't stall out. I saw the step-by-step guide for the ES/RX concerning the idle air control valve, but I can't translate that to the LS400. If I can just find where that is, that'd be appreciated. I read in another thread that it was under the power steering pump, but that just doesn't sound right -- it has to be around the throttle body/intake or at least the air filter area, right?

Seems simple, but when I looked online for one from the usual auto parts stores..... http://shop.advanceautoparts.com/ProductDe...506&PTSet=A $985?????? This much for what seems like a simple part?

The weather around my neck of the woods' been crazy these past few days -- raining and bitterly cold -- something you really wouldn't expect a lot of in the deep south. Hopefully the weather will let up enough this coming week so I can get some work done! Thanks for all of the advice B)

Thanks. I'll start looking at the IACV and track down any split/worn vacuum hoses asap. And now it seems I've lost the owner's manual, which I need to look up the interior fuse box schemata. Anyone have an online version that could help?

I removed the EFI fuse and relay in an effort to isolate the problem. Without both, it's not getting any fuel at all. Reinstalled, it gets fuel.....as long as you have your foot on the gas pedal. Otherwise, it won't receive fuel on it's own.

This car has a LOT of miles on it. 350k.....at least until the odometer broke. :o To my knowledge, there is no record of the fuel filter being changed. I'll double-check just to make sure and if not, I may just go ahead and have it changed out. Acceleration is no problem. The only trouble is keeping it at idle -- when my foot is taken off the gas, the car simply quits. I have to keep my foot on the pedal to keep it running. I've checked the fuel injection and MAF sensor. I don't see any problems, but I'll double-check when the weather isn't so inhospitable. The spark plugs and wires were changed several months ago (OEM spec if I recall...) and the oil and oil filter were changed just 3-4 months ago. One more thing: the transmission goes in and out of R and D with a SLAM above 1000 RPM. It's probably not related to the problem at hand and can probably be taken care of with new fluid or a flush.

I browsed a few threads with somewhat similar problems, but none of them really fit the bill. My car basically stalls out coming to a light. I doubt it's related to the trunk wiring -- and if it helps, I topped the car off with a full tank last night. I hope it's not bad fuel causing the problem.

Problem surfaced on the way home. I stopped at a red light only to see the RPMs fall to ZERO. Had to pop it in N and restart it, but now it won't idle on it's own -- I have to keep my foot on the accelerator to keep the RPMs up. At this point, I have no clue as to what could make a car that was idling just fine to suddenly stall if you don't keep giving it gas.

Hose down one of your rear wheels with water, then find a hard corner to charge into so you can see if the TRAC is kicking in.

Haven't done anything to it yet. Will talk to an independent tranny shop for a second opinion.

So I took my 92 LS400 to the dealer to have the transmission flushed. Service techs looked at the condition of the fluid (about a brownish red - I suspect the fluid hadn't been changed in a looooong time) and said "no way", since according to them the transmission had shed too much "clutch material" for them to do a flush without having to worry about premature failure. They said the thickness of the current fluid was pretty much holding it together. Now if this is so, then wouldn't a "drain and fill" with a bottle of Lucas Transmission Fix hold it together? And how long would I have before I see some serious problems? FWIW, the shifting is getting a bit harsher, especially going into 3rd gear.

Dang. The leather seats look better than mine. Both front seats have a nasty split in the middle of the front cushion. I bought my Lexus for $1500 and ended up having to spend about $2k just to get it in decent driving condition. At this point, I'm not sure if I'd be able to get back what I put in it if I sold it. :cries:

So far I haven't had any other problems out of the car. Someone on another forum mentioned the same thing happening to his BMW and chalked it up to the starter solenoid experiencing "thermal breakdown". The mechanic I spoke to also mentioned the starter solenoid possibly being bad. I hope that's not it -- otherwise I'll have to brace myself for yet another repair bill.

I think the PRND12L indicators were lit during those times, but I will keep a close eye on them if the car decides to strand me again. <_<

Pity that no one's bothered to chime in with an answer, but I think the problem has worked it's way out for the moment. Before starting the car up, I put the old relay back in just to see if it would work and well.......it did. Started right up with no fuss. Drove well, too. Got it back home after a 6 mile drive and turned it off. Cranked it up a few times and it seems that the problem wouldn't show itself again. I still believe that something in the anti-theft system got out of whack and bugged out on me. Anyone who thinks differently feel free to chime in.

By the way, the battery and alternator seem to be good, as I haven't had to jump the car off in order to get it cranked and running. And as a side note, I removed one of the H3C bulbs (both are stone dead) with the intent on replacement, but never got around to doing so. I have a hard time believing that something that insignificant would cause problems. Also popped a fuse back into the empty TRAC slot, although the starting problems happened well before I did this and I doubt this would have a bearing on things either. EDIT: I'll try starting it up with the old relay in place this afternoon. That might rule out one possible problem. If that doesn't work, then I'll try the other relay and work from there.

Okay, starting from the top: Had a dying starter replaced with an remanufactured OEM starter The A/C condenser fans stopped working in the process Replaced a broken part and patched up another Car's been driving just fine for over a month Now let's get to the beef of this problem. I drove out of town for a good 30 miles and made a stop. Came back to the car and it wouldn't crank. At first, I thought I triggered the immobilizer on the car (which disconnects the starter circuit) by fiddling around with the door lock, because I ended up getting tripped up over which way to turn to get the car unlocked (earlier I was driving another car whose door locks/unlocks in the opposite direction). I disconnected the battery for a good couple of minutes, thinking that the anti-theft computer was on the fritz, fiddled around with fuses, found a blown 15 "CIG" fuse, then made my way to under the hood of the car, where I ended up diagnosing the problem as a bad starter relay. Left the car, hitched a ride and went to bed. It was late night and there wasn't much I could do about it then. Came back, new starter relay in hand. Took the advice of a former Lexus owner who was having problems out of her anti-theft system and unlocked the passenger's side door first (not that it made any difference IMHO). Put that one in.....and it cranked up with no trouble whatsoever. Drove it back home and parked it. Came back about 25 minutes later, unlocked the driver's side door, hopped in and...... ........it wouldn't start. As luck would have it, a mechanic came by and helped try to figure out this fustercluck. He thought the old relay was still good and that the problem was with the starter that was installed, or more specifically, the solenoid. The starter relay was still engaging, but the starter wasn't saying ANYTHING. No clicks (except from the relay), no nothing. Told him the circumstances of when it started (cold engine) and when it wouldn't start (hot engine, running for about 45-50 minutes). Don't think any of the other relays are bad and I'm wondering if the anti-theft is locking down the car sans alarm every time I move it. I really hope it's not the starter, seeing as I sunk about $600 in parts and labor into it in the first place.

I realize I'm bumping an old topic, but I have this very same problem. While replacing the starter, some sort of bi-metal valve was broken off, along with a couple of other items. They were eventually replaced or glued back together (with a combination of crazy glue and silicon gasket :D ), but the A/C still isn't cooling. A mechanic checked the condenser fans and noted that there was no power being delivered to them. I enjoy my A/C very much in the humid heat of the Deep South and I need a solution to this problem pronto!

Thx buddy. I added some water in the reservior when i checked for the level. it all water in the plasyic tank. wht kind of coolant to fill? thx in advance. Water isn't gonna cut it. Normally you would use red coolant in there. Now if someone is kind enough to give us the proper name....