glenn2726

Hi all, it seems that there are lots of posts with people helping each other out here but most come to a dead end with the poster not letting others know what the final resolution was to his/her problem. Would be nice if everyone took the time to post an update once their vehicle had been repaired so others could read. Some posters go out of their way to post the final resolution and I'd like to say Thank You to them. All help is appreciated here and in order to show that appreciation we should all try and post what corrective action worked. Thank You to all and keep up the good work.

You need to do a search as there have been many of these same posts.....first thing to check is the grounding wire from neg battery terminal, then alternator...good luck

So are you powering the sub with your deck or with the amplifier next to the sub? Looks like from the drawing the D9 and D10 wires are the ones to tap if you are powering with your own amp or deck. Do you have 12 volts at the amp? What are the connections you used to connect your aftermarket to the wiring in the Lexus, will be switching mine out with a DVD with screen so I'd like to know if you found connectors to go from your stereo to the factory harness and which wires for the antenna? Thanks for all your help in advance.

Yep good advice, sounds like the alternator is going bad, might check to see if your Power Steering Pump is leaking onto the ALT....that would definitely cause it to short out....good luck

Hi all have been searching for the code 25 fixes but have only found symptoms and no responses to what repairs were made. After having my transmission replaced I now have a CEL and shows code 25. Would like to know what others have found and where I might look first to find what needs repair. I have a 92 Lexus SC400 and it runs and idles fine. I only get the CEL code 25 after driving on the highway at higher rpms and speeds. It's only 11 degrees out right now so not gonna work on her today so just thought maybe I could get some help here first and then when it is warmer tomorrow try and tackle the problem. Thanks for all your help and any input is appreciated...

That's Great Phil, glad to hear you got it sorted out and back running again. Those codes are hard to interpret but as you said a good Lexus mechanic can save you some time and money in the long run. Hope that's the end of your problems.

Update, got my SC back yesterday and all is well with the transmission now. Was cheaper than letting them rebuild the other one. The swap including flushing tranny fluid from radiator, new seals, new filter, new tranny fluid, etc was $400. So I don't feel too bad.

Hi jzz30, yeah been watching ebay and checking out the salvage yards but no luck. I just need the top part of the drivers seat. Rest of the seats are good. Hate to have to replace them all. Great site here.

Update...Took it to transmission shop yesterday, took a while to drive it over as when I pulled up to a stop light...it wouldn't go, turned engine off, restarted a couple of times and had tranny again....then got almost to the tranny shop and it quit again, truned off and restarted a couple of times and had tranny, made it almost to the entrance to the shop and parked it.....Well transmission shop called this morning and said the tranny needed rebuilding, so much for it being a solenoid or anything more reasonable....talking about $2500.....geez...luckily I have a spare tranny so took it over to have them swap it out for about $400. Hopefully that will be the end of tranny probs...will keep the other tranny for parts in the future as solenoids are expensive for these things....Good luck all and thanks for the reply GoGreen.

Hey Phil, you took the IACV out that is at the very front of the engine? It is difficult to get out but I know mine was dirty and solved my problems after cleaning it. I can't believe yours was clean with all the problems you are having with it. Let me know if we are talking about the same part. It has small antifreeze line connected to it and bolts to top front of engine. Good Luck, Glenn

My SC400 has a big tear in the driver seat back. Anyone got one they're selling or just the seat cover? Thanks

No replies.... Well I dropped the tranny pan yesterday and cleaned the filter and replaced pan and replaced fluid with Toyota IV and was able to get the car moving. It shifts through the gears but then after it warms up it starts slipping again. Didn't think I was gonna make it home......and just went around the block. It started flashing the OD off light and the Oil Level low lights and wouldn't go in gear. Turned it off and restarted and it went into gear again.....go figure, so I tried it again today and same thing. Will be taking it to a transmission shop tomorrow, maybe it is a shift solenoid or something. At least I got it to move.

I know what you have been through as I went through the same with my first SC400, it would surge at idle, would even act up at highway speeds. I tried a different MAF, cleaned injectors, you name it...and no change. The Toyota shop told me originally it was the MAF and it was like $800 used....but got one off of ebay for $100. I then discovered the IACV and once I got it off found it to be the culprit....it was so dirty inside that it would not move freely, so I cleaned it up and put it back in and my Lexus purred again and was so smooth at idle....anyways this must be a secret because I don't read about it much. It is a treat to get off the engine because of the hoses that connect to it, not much give, but once you get it off of the engine and clean it and put it back in you will be happy with the results. These things are an expensive part from Lexus so it's great that it just needs cleaning. Good Luck and hope this takes care of your problems.

Another thing that causes the same symptoms is the IACV Idle Air Control Valve, located top front of engine, those get carboned up and will make your car have bad idle, and even at highway speeds will act up. All you have to do is take it out and clean it good so that the insides move freely again. Good luck

Could also be the Idle Air Control Valve needs cleaning...located front top of engine. If that is dirty and not moving freely inside then your Lexus will not run well. This is usually the problem and not the MAF that causes the surging and erratic idle. Hope this helps.

Hi all, just acquired a 92 SC400, it is the blue/gray color. My other SC400 is Black (and still waiting to be put back together from engine problems. Now the latest addition I bought and the guy said that the transmission was out in it. I start it up and put it into any gear and no movement, when I rev it up it seems like it wants to go but nothing. Checked the fluid and it looks clean and no burnt smell to it. The car has 205.000 miles on it but has always been serviced by Lexus so don't feel that the transmission is really hurt, just need to know where to start. Transmission is not making any noise and no leaks. Does this sound like maybe the transmission filter needs cleaning or more like the torque converter is out? Or?? Thanks for the help and hope to get the newest addition on the road soon. Glenn

Had the same problems, replaced MAF, tuned up.....etc....etc....the problem is the Idle Air Control Valve....located on the front of your engine, you'll have to take it off the engine and clean it out and make sure it is working smoothly before putting back in engine. Once done you'll have smooth idle and no more bucking....good luck

Angelos the MAF or Mass Air Flow is part of the cold air intake and located passenger side engine compartment. I had idle problems with stalling and the idle would fluctuate all over the place and after doing tuneups, replacing MAF etc.... I found the problem to be the Idle Air Control Valve which is located on the front of the engine. That is what controls your vacuum and it is susceptible to carboning up. Just take it off and clean it good and make sure it is moving freely inside and it will solve your idle problems. Good Luck

Hi I just posted a couple of replys to other posts for the dreaded idle and hesitation problems.....check out my reply to Applejack.....what I eventually found is that it was the Idle Air Control Valve that is located on the front of the engine under the plastic spark plug wire cover....it is about an $800 part from Lexus....but you can remove it and clean it....it gets carboned up and wont spin in and out freely and mine was stuck fully open. Once cleaned with carburetor cleaner it works like a charm. It controls the amount of vacuum your engine uses so if it is stuck or not freely moving then your idle will not be steady....Hope this helps everyone that has been pulling their hair out over this problem...now you can sit at a stop light and not have to keep your foot on the gas pedal....java script:emoticon(':)', 'smid_11') :)

Hi, check my reply to Applejacks idle problem, sounds like yours is the same, it's the Idle Air Control Valve located on the front of your engine, it controls the amount of vacuum your engine needs to run smoothly....

Hi, I had the same problem as you do and as many others on the forum have had, I did everything to try and cure it that people on here have done, ie....plugs, wires, distributor caps and rotors, clean throttle body, clean mass air flow (even had a code showing mass air flow was bad so changed it out...no change), and more.....but still had the same idle problem, hesitation and sounded like I had a race cam installed. I finally found out what the problem was......check your idle air control valve...it is what controls the vacuum for your engine....it is on the front of your V8 right under the plastic housing for your plug wires, it is round and has vacuum lines running to it as well as lines for coolant. I think it is an $800 part from Lexus, the Mass Air Flow Meter is $1600. It's easier to pull the whole assembly off the motor and then disassemble it once you have it out as the screws holding it together are easy to strip out...once off the engine you will notice a rod that should move in and out as it spins which adjusts the amount of vacuum your engine needs....it will probably be stuck in the full open position as mine was due to carbon build up...take the three screws out holding the assembly together and then with carburetor cleaner clean it until the rod moves freely....it has spring tension so that it can spin in and out, once cleaned and moving freely then check where it was mounted to the engine and make sure the inlet is cleaned and not clogged with carbon...then reassemble unit, remount on engine and it's also a good idea to pull your negative cable on the battery to reset your computer. Once that is done then start your new smooth running Lexus V8 up......Mine was hard to start and keep running after the cleaning, don't know if someone had adjusted the idle on it in the past or what but I had to adjust the idle screw a bit and once that was done it idles at about 600rpm when warm. Just like everyone else on here I pulled most of my hair out trying to figure this one out..... hope this helps. I bought my 92 Lexus SC400 about 2 months ago and love it now that the idle problem is solved.