Razor61

After a week or so driving to work and back I’m sure the rebuilt ECU has made a difference, not as much as the ‘spare’ ECU made but a definite improvement over that. Lower end torque is better for sure, not easy to describe but you can ‘feel’ it when driving. Another thing is the cruise control is better, it doesn’t fluctuate as much and is more stable. Probably due to the lower end torque improvement. Gear changes seem better but I can’t swear to it. I can’t say anything about MPG yet until I go for a decent run, it’s about the same going to work and back though.

Hi Oli, interest noted and will have a think about it👍 Good luck in your search, members will be more than happy to give their opinion on any potential purchases. There are a few decent looking LS400's for sale at the moment, emphasizing decent 'looking' cars - reality may be very different. Gold 96 in Sutton and White 98 in Middlesbrough on Autotrader White 96 in Glasgow and Silver 98 in Chichester on ebay, the white one has stuff in the MOT history which would concern me though. There are others on eBay and Autotrader which have been for sale on and off for quite a long while.

This one looks decent, not a mk4 but it looks very good. Registration number not visible or in the advert which would put me off a bit but it's a case of asking the seller for it. https://www.autotrader.co.uk/car-details/202306299063054?advertising-location=at_cars&atmobcid=soc5&fromsra&include-delivery-option=on&make=Lexus&model=LS 400

Thank you Stan, the picture was not long after I'd detailed the paintwork (clay bar, machine polishing/buffing, 3 coats of wax etc) so it looks the best it can. The car needs the clay bar treatment again this year because of tree sap and other stuff on the paintwork but it still looks very good. I've gone off the idea of selling it now, sensible side of my brain kicked in🙃 But.........................as I've said before, if someone offers me £10k I would take it. Extremely unlikely I know but you have to decide on a price just in case🤣

Carriage to send it the USA was £46, cost for the ECU rebuild was £400 + £48 carriage from the USA back to me. Total was £494 in total for my ECU, price for a rebuild is dependent on if and how much remedial repair work needs to be done i.e pcb repairs due to leaking caps and corrosion.

Just thought, I forgot the car was still warm and it fires up straightaway anyway when warm so that's no different. A couple of cranks this morning when cold so that hasn't changed. Was there any difference driving 10 miles to work? I believe there is a difference and feels even more responsive, it feels quicker and I don't have to press the accelerator pedal down as much. But it's early days and this may be all in my head...............the more I drive the car the more I'll be able to tell plus it will take time for the ECU to adjust correctly. This is a definite though: Swopped the original ECU for the 'spare' ECU - 100% sure the car performed significantly better. I can only assume the 'spare' ECU capacitors etc were more efficient and in better condition than in the original ECU in the car. Time will tell if the rebuilt original ECU has improved things again, I think it has but as said above I need more time driving the car to make a judgment. Initial impressions are good though. You never know, the car may be able to get near the quoted performance spec of 0-60mph in 6.3 seconds, which is pretty quick for a big car and pretty quick by any standard tbh. When everything has settled down I'll find out🙂

ECU update…… Received the rebuilt ECU back from Bill in the USA, very professional service and shipped back to me without any hassle and packaged excellently. Fitted it to the car after work today, connected the battery and left the ignition on for a few mins before starting, as instructed. Put the key in and turned, car fired up immediately and I mean immediately with no cranking. Good sign that it was worth doing. Tomorrow will be interesting going to work and I will be able to give more info on what difference/s it has made to the car. Main thing is it works and the caps have been replaced to prevent any issues in the future. I now have a spare good ECU, proven in my car for the past 5-6 weeks, with a master key and an uncut blade. It is for sale now if anyone is interested in doing what I have done. I’ll update this thread again tomorrow after work or maybe when I get to work, tempted to go for a drive now but it can wait until tomorrow.

The bottom 2 rollers are held in place with a very large grub screw and is locked in place with a large locking nut/ring. Flat roller contacts the steering shaft, 3 concave washers ( concave side up towards the steering shaft and roller assy) then the large grub screw and locking nut. I used a paint pen to mark where the grub screw is, removed everything, cleaned with brake cleaner, greased the roller assy, applied grease to the steering shaft through the vacant hole then reassembled both rollers. Of course it’s easy out of the car but I’m pretty sure I can do the same thing on the car no problem, I know now how it all works and what bits to remove and reassemble. spanner used was a 32mm, I think it’s a 31mm nut but 32mm did the job.

Ok, received the steering mechanism today and had a good look at how it all works. First thing the tilt plastic gear is in perfect condition, I think the worn plastic gear is caused by owners using the steering wheel to lever themselves out the car while the steering mechanism is returning to its default position. This puts a lot of pressure/strain on the tilt plastic gear and therefore wears the plastic teeth. Better to wait until the steering mechanism has stopped before getting out of the car, which is what I do. The telescopic part is held in place by 3 rollers, 2 flat rollers on the bottom and 1 ‘bobbin’ type roller on the top. Top roller: This roller is held in place by a roller ‘carrier’ with a pin through the carrier and roller. I knocked out the pin and removed the roller carrier and bobbin style roller. Cleaned the roller , used some scotch bright pad to remove slight corrosion on the roller, applied some moly grease to the steering shaft through the vacant hole, applied the same grease to the roller etc.

Oil and filter change on the IS250, washed, polished and then sorted out the oxidised headlights again with DuxBack (lasts 12 months or so) then washed the LS400. Both cars rinsed with pure water (same as window cleaners use) and when the water dries it doesn’t leave any spotting on the paintwork or glass. Took 5 hours, now time for a beer and watch some Ashes Cricket😀

Ah yes, the steel washer fix for the tilt mech plastic gear..........same setup for the mk4 or series 2a as well up to 08.1998. The same main assy was used on the LS400 for production dates 10.1994 - 08.1998 - the tilt motor part number changed but looks the same. 08.1998 on uses a different type of mechanism. My 1998 mk4 or series 2a with production date of 01.10.1997 has the same tilt motor mechanism as the mk3 or series 2 using a worm drive with the plastic gear. I'll look into the plastic gear thing when I get the used assy. I'll maybe investigate making a new plastic gear, just out of interest.

The telescopic and tilt mechanism on my 98 LS400 has been bugging me cos it’s noisier than I think it should be. Some cars I looked at had a quiet mechanism. Sounds like the telescopic motor is struggling for some reason but it all works ok. So last week I decided to have a good look at how it all works, my car has a different mechanism to the 99/2000 LS400. The 99/2000 is very similar to the LS430. If you look on the EPC website you can see the difference. So last Wednesday evening I removed the covers around the steering wheel to see if I could see and then get to the sliding tube for the telescopic bit and the gear assy for the tilt bit (which is a proper piece of kit and engineering, it’s impressive) I could get to both of them and applied some grease using a syringe, worked the mechanism’s up and down to get the grease moving around. It made a bit of a difference but nothing drastic. I suspect the guides mentioned below need some attention. The telescopic bit has 2 spring loaded guides underneath to keep the tension and stop it moving around but has to be torqued to 8nm iirc so it’s not too tight. I have the workshop manual to adjust it all etc but didn’t fancy doing it at the time and it’s a journey into the unknown plus I was going on holiday Thurs until Monday in the wife’s IS250. I thought I’d set the interior light to ‘door’ on the car but turns out it was ‘on’ so came back to a totally flat battery when I went to the car Tuesday morning, rookie mistake but a good charge all day Tuesday and overnight fixed it. Over the weekend the thought crossed my mind to buy a second hand assy, have a good look and work out what I need to do to make it quieter without experimenting on the car. Of course if the price is low enough. This morning I found the correct assy complete with all the motors on eBay and promptly bought it for £45 delivered, result. When it arrives I’ll have a good look and work out what I need to remove, clean and grease to hopefully make the assy on my car quieter and smoother. I’ll take pictures and document anything I figure out and post it here which may be helpful to someone.

Pic of the car from last year with DHP alloys.

Might be a surprise but I am thinking of selling my 1998 LS400. Most people will know what the car is like and the work that has been done. I would hazard to say that it might be the best mechanically and the best driving mk4 or series 2a LS400 in the UK, in my opinion of course😉 The car is not ‘perfect’ on the body but I would say it’s excellent condition and you would struggle to find a better combination of body/mechanical /driving/suspension/electronic/electrical condition in the UK. That is before I receive and fit the rebuilt ECU. So why am I thinking about selling? Answer is that I fancy changing to an ISF (first choice), SC430, a good LS430 maybe or maybe a GSF. Thought about a LS460 or LS600H but the suspension replacement costs are ridiculous even when buying from Amayama. I know I will never get a price that covers what I have spent on the car, I am realistic, but I think £6k - £7k is maybe achievable? What do you guys think? I’m not hell bent on selling at all but if someone on here appreciates the car, what has been done and knows that it’s good for 100k at least with correct maintenance then I would be willing to have a conversation.

Not got the plugs but I have looked at a spare cluster I have to determine what IC/chip needs to be reprogrammed. This is for a 97-2000 LS400, earlier models will probably be different. The IC/Chip is IC8 on the main board, it is a surface mount IC, same size and shape as the immobiliser IC/chip in the ECU. I tried reading the chip ‘in circuit’ without removing, same as the ECU immobiliser chip and can’t do it so needs to be removed. I am confident that once removed it can be read and reprogrammed for the correct mileage. However, my opinion is that if anyone needs to replace the cluster and keep the mileage correct then either swop the main circuit board if it’s ok or swop over IC8. IC8 is located under a heat sink for voltage regulator IC1 so the heat sink needs to be removed and is fixed with a bolt, spring washer and nut.

Ah, I see what you mean about the 2 sets of adaptations. It’s possible I suppose, there is a clear memory function in Techstream so will try that.

Nope, I've had the battery disconnected lots of times when testing the spare clusters and audio/satnav units plus when replacing the Yaw Sensor and for other reasons. So the 'adaptations' have been reset multiple times on the old ECU. Normally I would just reconnect the battery and away I go but I found a TSB outlining how to reset the 'adaptations' and the correct method to help/speed up the learning process. When I fit the rebuilt ECU I'll follow the TSB instructions. ECU_Clear_Learning_memory.pdf

You’re welcome, the replacement ECU I installed in the car performs better than the ECU from the car that I sent to Bill (LScowboyLS guy) for the rebuild. I didn’t want to say anything until I was sure but the car definitely performs better and not just slightly better, quicker off the mark, more powerful and shifts gears better. Caps are not ‘as bad’ I presume. Seems to start better as well but I can’t be 100% about that. Looking forward to fitting the rebuilt ECU and see how much it improves the running of the car. It’s difficult to ascertain if the car is performing and running as it should because you can’t compare it to a brand new LS400, I’ve not driven a new LS400 or very new LS400. Strange thing is that the MPG on a long run at motorway speeds is worse but the MPG going to work and back is better. This illustrates the differences between the same ECU’s due to varying degrees of the capacitors efficiency and how well they are working or not working.

No problem, Brakes International are really good. Handy for me being so close to where I live as well.

I've used Brakes International for brake stuff and calipers for other cars in the past and their Budweg refurbished calipers have always been excellent. The ones I bought were refurbished OEM calipers i.e. BMW E46 M3 calipers had the M/// logo in the casting. I'd bet the LS400 calipers are the same. They have the RH LS400 caliper in stock but not the LH. You can email them to ask about availability and when they are likely to be in stock. Buying the seal kit and 8 x new caliper pistons from Amayama is around £140 with a refurbed caliper from Brakes International being £140. So £280 for the refurbed calipers, used ones on eBay are around £300 for a pair..................... Me personally, I would replace them with refurbished calipers from Brakes International (if they can provide the LH one at some point), which is the quickest option with no need to be without the car while the calipers are refurbished, then sell the old calipers to someone who can/will rebuild them. https://brakeparts.co.uk/shop/Lexus/Ls400/95-00/Ls400 Ucf20 4.0 Petrol/Front - Brake Calipers and Wheel Cylinders

Update to this. Tonight I replaced the capacitors on an early LS400 ECU part# 89661-50050 The ECU is a ‘dual board’ type and it wasn’t a problem for me to replace the capacitors being careful and figuring out the best way to do it. Vastly different to the 97-2000 single board ECU which is a different beast. Having a thin stainless pin of some sort is essential to ‘make’ the holes through the board to install the new caps, as described in other posts, but getting one is another story. I found some safety pins but they were not stainless, I used a magnet to find out. In the end I found a thin power washer nozzle cleaner thing, stainless and the perfect size. Good idea is to watch videos from Mr Solder Fix on YouTube. if you are going to attempt this yourself this is a good tip which I saw on a Mr Solder Fix video. Once you remove the capacitor and ‘make’ the holes in the board, fit the capacitor - tack one leg - clip the legs to the correct length - apply some flux to the pads - solder the ‘un tacked’ leg - then solder the other leg - when soldering count for 3 seconds while applying the solder - check the other side of the board to check the solder has run through ok - if not apply the soldering iron again for 2-3 seconds and check again. Clipping the legs reduces the amount of metal to absorb the heat from your soldering iron, just my theory but Mr Solder Fix does this.

I started to do exactly that but changed my mind, I figured this is more of an ‘information’ thing. I will create a How-to guide for the EEPROM chip removal, not soldering, and programming though.

I know there are other topics and posts about this but I wanted to collate all the information I have gathered in one place. If you need to replace the ECU on your LS400 or suspect you have a bad ECU, this information will hopefully help and is correct to the best of my knowledge. Normally this is needed due to a bad ECU and is normally caused by bad or leaking capacitors, well documented here and other places for the reasons why. If you are not experiencing any issues that you know of, having the ECU rebuilt correctly with the correct replacement capacitors is a good idea in my view. Your car may be off the road for a while but 'An ounce prevention is better than a pound of cure'.......................as the saying goes. All this information is a combination of my experiences and information I've gathered from various sources. If you think anything is not correct then let me know and I'll update this. ECU replacement: Model years 1989 - 1994 aka Mk1/Mk2 or series 1 and series 1a - ECU is a 'dual board' design, can be swopped out and should just work. If the replacement ECU is in a working state. I have been told by an 'expert' in rebuilding ECU's that the capacitors just go bad and don't normally leak causing PCB damage and corrosion. Replacing the capacitors correctly and with the correct type and quality is normally all that is needed. Once rebuilt correctly with the correct replacement capacitors the ECU should last a long time. This can be a DIY job if you know what you are doing with a soldering iron etc. but I would recommend an expert do this. Model years 1994 - 1997 aka Mk3 or series 2 - ECU is a 'dual board' design, can be swopped out and should just work, I have done this with no issues. If you can find a replacement and the replacement ECU is in a working state of course. I have been told by an 'expert' in rebuilding ECU's, and reading information on forums, that these ECU's (there are quite a few different types) are the most common for bad and especially leaking capacitors causing PCB damage. If your car is experiencing strange issues relating to bad capacitors then it may be too late and the PCB has been damaged too much by capacitor leakage. The only way to find out is to remove the ECU and have it checked out. The ECU PCB/Tracks may be fixable by an expert/someone who knows what they are doing and then replace the capacitors. This can be a DIY job if you know what you are doing with soldering iron etc. and the PCB isn't damaged by leaking capacitors but I would still recommend an expert check it all out and do this. Model years 1997 - 2000 aka Mk4 or series 2a - ECU is a 'single board' design and cannot be just be swopped out and will work. This is due to the immobiliser that is integrated into the ECU, previous years did not have the immobiliser integrated into the ECU. This model/version of ECU's suffer from bad capacitors and capacitor leakage and can cause damage to the PCB/Tracks. I have been told by an 'expert' in rebuilding ECU's that there normally 'is' capacitor leakage but it's not always easily visible and needs examining carefully to find it. These ECU's are more difficult to work on to replace the capacitors, I know from experience. Because the PCB is a 'single board' design and has more 'layers' than the earlier 'dual board' design ECU's, the amount of copper in the tracks acts as a big 'heat sink' which soaks up the heat from the soldering iron. Replacing the capacitors is best left to an expert who has the knowledge and equipment to deal with it. Maybe pre heating the complete board will help with this but what temperature to heat the board to safely I don't know but an 'expert' will. If you can find a replacement ECU, ideally one that has been rebuilt with new capacitors or you have it rebuilt with new capacitors and any damage repaired, and you have a matching 'master' key fob then you can swop it out. You can use the matching master key 'innards' and add your existing master keys to the ECU/Immobiliser. If you have a replacement ECU without a matching 'master' key fob then there are some options. 1. remove the immobiliser chip or IC (IC900) from your original ECU and replace IC900 on your replacement ECU with it, basically swop over the immobiliser chip or IC (IC900)and your existing keys should just wok. Not a DIY job for a novice, you need good soldering skills with surface mount components to remove the chip without damaging the chip or the board solder pads. Better to have an 'expert' do it for you unless you know what you're doing. 2. remove the immobiliser chip or IC (IC900) from your replacement ECU and reprogram the chip so all the 'key' information is removed and is in 'Auto Programming Mode' as if it is a 'brand new' ECU. Fit the replacement ECU and your existing keys will be programmed to the ECU following the instructions in the video below. I found this video to be the most useful for this: https://youtu.be/OxvMeMo-j_A As in option 1 above, not a DIY job for a novice, you need good soldering skills with surface mount components to remove the chip without damaging the chip or the board solder pads plus an EEPROM programmer and software. Better to have an 'expert' do all this for you unless you know what you're doing. I have used this method on my 1998 LS400 with a replacement ECU that didn't have a matching 'master' key and it works, replacement ECU is in the car and working with the original ECU on it's way to the USA to be rebuilt. I hope you find this information useful.

I’m not bothered about sending it back, it wasn’t an OEM Lexus/Toyota key and it was a bit of a punt on my part as to whether it would work or not. It’s probably ok and will work with other cars but not mine, maybe down to the frequency of the transmitter or something. Fortunately I didn’t get it cut to the ignition barrel cos there was no need, just removed the innerds and put in one of the other cut keys.