Razor61

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.

Now rebuilt with new updated capacitors as per ‘LScowboyLS ‘ - ‘all my crazy ECU’s issues…..’ post/topic spec so all ready to rock ‘n’ roll.

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 have a LS400 mk1 89 - 92 ECU for sale part# 89661-50050 I’ve checked the condition, observing anti-static precautions, and there are no leaking capacitors and therefore no damage to the pcb or pcb tracks that I can see using a magnifying glass. It’s a prime candidate for a rebuild and replace all the capacitors to put in your car. Condition: as stated above clean untouched condition apart from an examination by me. Price: £250. Price may seem high but if it saves your mk1 LS400 it’s worth every penny.

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.

Small update to follow on from yesterday. When the ECU is in ‘Auto Programming Mode’ for new keys after the immobiliser reset, as if a brand new ECU has been installed, the ECU wants 4 keys programmed before it will exit/end ‘Auto Programming Mode’, with the final 4th key assigned as a Valet key. I knew this, hence the reason I bought an eBay key so I then had 4 keys, which didn’t work in the end and only my existing 3 x keys could be programmed. If the 4th key isn’t programmed, the car/ECU stays in ‘Auto Programming Mode’ for days/weeks/months with the security light flashing when a programmed key is inserted until it eventually gives up. A bit annoying, even though this is a ‘temp’ ECU but the car still starts and runs so no big deal. However, while playing around with Techstream this morning connected to the car, to see if there was a reset/clear function for the immobiliser, I noticed a very nice utility to end the ‘key’’ Auto Programming Mode. So gave it go and no more flashing security light. Checked how many keys are programmed to the ECU and it’s 3 x master keys, which is correct for what I’ve done. Even with Techstream a master key is needed to clear keys etc, so Lexus were correct about this. This post is a mixture of information, trial and error, failure and then success in the end installing a used ECU with the immobiliser chip ‘reset’ so ‘keys’ can be programmed to ECU and car will start and can be used. Now I have a full/fulller understanding of what’s needed and how to do it, I’ll either create a new post or a ‘How to’ guide dealing with just the immobiliser chip ‘reset’ stuff.

For the immo chip programming, this is a better video. Chip type in the programmer should be set to 93c56 16bit https://youtu.be/OxvMeMo-j_A

The ‘new’ plan worked like a dream apart from the eBay key. Soldered the re programmed immobiliser EEPROM to the board of the spare ECU, I practiced on a scrap pc board and all good. When it came to the spare ECU I was shaking like a leaf😀 Calmed down enough to get it soldered, cleaned up the flux and reassembled the unit. Disconnected battery on the car and removed the ECU, installed the spare ECU, connected the battery and it was in programming mode for the ‘keys’. Programmed my existing 3 x keys but the eBay key didn’t work. Inserted one of my original keys and it started no problem, tried the other 2 keys and they worked as well. The eBay key I’ll have a go at again, not hopeful though. All things considered I’m very happy, I can send the original ECU from the car to be rebuilt and still drive the car. I’ll update this bit again when the ECU has been rebuilt and installed back in the car. When I get some plugs to power up the spare cluster on a bench, I’ll have a go at the mileage correction.

Thank you Sir By the way, I visited Lexus Bolton yesterday and asked if they could reset the immobiliser. Answer was no, you need a master key.

The immobiliser chip ‘project’ continues……. Yesterday I removed the immo chip from the spare ECU, stuck it in the EEPROM programmer and successfully read the ‘key’ data and saved the ‘dump’ file (which is basically all the data in a file format as a backup and can be edited) Today I edited the dump file mentioned above to remove all the ‘key’ data and left the ‘dealer codes’ or something similar. Saved the dump file with an appropriate name and then wrote or programmed the new data to the immo EEPROM. Disconnected everything, reconnected everything and then read the data from the chip to make sure it had actually worked. All good and chuffed that an old dog can learn new tricks🤣 The ‘new’ plan, now I have a reset immo chip, is to solder it back on the spare ECU, put a new cap where I’d just remove a cap and left it, stick the spare ECU in the car and see if the ECU is in ‘key’ programming mode as it should be. If it is I’ll programme in 2 of my existing keys, 1 master and one valet, and another I bought off eBay as a master that hasn’t been programmed at all and see if the car will start and run. If that’s successful I’ll leave the spare ECU in the car and send the original to Bill to rebuild it. Once I have the rebuilt ECU back I’ll fit it, the spare ECU I will then put up for sale with a master key, the one from eBay mentioned above, so no need to remove the immo chip and reprogram………simples😀 But of course all that may change again.

There are companies that will replace the caps but they need to be the ones specified by LScowboyLS which are not readily available in the UK, I ordered lots from DigiKey in the USA. I still have them all but I won’t be using them. Bill aka LScowboyLS has done this work for years and doesn’t just replace the caps with the ones I’ve bought and anyone else can buy, although they are are a vast improvement on the originals. He uses special or super caps which he has researched along with a specialist in Japan, no info on what they are apart from that. All the work is to Denso spec with care and attention using, for example, a microscope to check the board and soldering. I’m told and read that you cannot tell at all that any work has been done but it has. Of course the proof of the pudding will be when the job has been done and I’m repeating what I’ve been told or read. One other thing, there is a cap on the VVTi ECU that is bi-polar which means it doesn’t have a + positive or a - negative as normal. Caps normally have a stripe or indicator to show the polarity. When I tried replacing the caps myself I drew a diagram of the caps on the board, polarity, where they are and what value, i.e. C101 - 10uf 50v. I noticed one cap without a polarity indicator, didn’t think much of it and marked the polarity as all the rest cos they all faced the same way but during my correspondence with Bill I sent a picture of the diagram I’d made. He said I’d got some of the values are wrong, I checked and said ‘I don’t think I have’. He then said that it wasn’t the values but one of the caps is a bi-polar cap, my memory kicked in from years ago repairing TV/audio/video and the penny dropped. That convinced me he was the right guy to do the job. After all that, the point I’m trying to make is that on the VVTi ECU there is more to it than just replacing the caps. The board needs to be checked for any leakage (however small), repair board if needed and it can be done, replace caps, soldering to Denso spec, clean to as new condition and check all the work which is a brief outline of what Bill does. The earlier ECU’s are more straightforward I think and replacing the caps is probably not a big deal and I could probably do them no problem, the VVTi one though I really struggled as mentioned earlier. I practiced on a scrap computer pcb beforehand and didn’t have an issue, there is something about the VVTi ECU that’s more difficult to work on and Bill did say that.

I don't know exactly yet, I need to take the existing ECU out the car and ship it the USA. Cost for a standard ECU rebuild by the guy I'm using is around $400 plus the shipping cost to send it back to me and approx £40-£50 for me to ship to him. I'd guess at around $500 - $600 so about £500. If an owner plans on keeping their LS400 long term it makes sense to get the ECU rebuilt and it will be good for 20 years, just my opinion of course. Don't want to be without the car for a few weeks hence the plan to install a used ECU that will work while the original is being rebuilt. Probably won't do that now and will just take the car off the road for a few weeks, take a weeks holiday in that time and work on any rusty bits underneath the car. There's not much but I want to at least remove the panels covering the cills and treat/paint all the rusty bits on the cill seams around the jacking points.

The capacitor issue seems to affect the early Mk1, Mk2 and Mk3 more than the 97-2000 Mk4 or series 2a (the cutting out issue is a Mk3 thing) Whether this is simply down to age because of the capacitor type used I don't know but I suspect that it is down to age and the capacitor type used, probably the 97-2000 models will start to show signs of capacitor issues but maybe not as bad as the earlier cars. I know of a few series 2a 97-2000 LS400's that have had bad caps on the ECU's. The design on the ECU's changed for the 97-2000 VVTi models, they went from a dual board with a big ribbon connector on the earlier cars to a single more complicated multi layer board for the 97-2000 models. Maybe the VVTi model ECU's are better regarding the capacitor issue. However, if you read the topic/s below it's a case of 'when' not 'if' the capacitor issue will occur on the LS400 for all models. The caps go bad without leaking and go bad with leaking and can ruin the pcb/ecu. In my case on my 98 VVti, I haven't experienced any issues that I know of. However, Techstream diags won't do a health check on all modules on the car. It will do a health check on individual or a few of the modules ok, I haven't used it a lot but when I have used Techstream it's a bit flakey and intermittent. Maybe it does have capacitor issues and I don't know about it. I'm doing this for prevention and as a bit of a project, that's all. Having the ECU rebuilt by a real expert in this field of expertise will prevent any issues, that's the most important bit, bonus may be that the car will run better. I'm told reports are that after the ECU is rebuilt (by 'Lscowboyls'), low down torque is better and mpg is significantly better. If that's the case then it will be a nice bonus. I've conversed with 'Lscowboyls' a lot for this, he is the best person to do this and it's not just my opinion if you do a web search or some research. Useful links: https://www.clublexus.com/forums/ls-1st-and-2nd-gen-1990-2000/656360-all-my-crazy-lexus-issues-solved-ecu-leaking-capacitor.html Link to 'LscowboyLS' posts and there is a post about how to check if you have the capacitor issues. A bit technical and involved but the information is there. https://www.clublexus.com/forums/search.php?searchid=25933349

So the immobiliser chip ‘project’, tried reading the immo chip ‘in circuit’ or ‘on the pcb’ and no joy, even with shorting out the oscillators. Took the plunge and removed the immo chip from the pcb, easier than I expected. Inserted the immo chip into the EEPROM reader and hey presto I could read the data, promptly saved the data to a file on the computer and I’ll examine it tomorrow and edit it to ‘virginize’ it so it will accept 3 new keys. Before hand I practised removing the same type of chip on a scrap computer pcb to give me some confidence that I’ve not totally lost my previous soldering skills😀 By trial and error using a hot air soldering rework station I’ve realised I’ve not totally lost it.

I've had a rethink about all this after my epic failure😉 The original plan to rebuild the spare ECU (cap replacement) and reset the immobiliser has been scrapped, instead I'll be sending the original ECU out of the car to 'Japanese ECU ECM PCM Repair' aka 'Lscowboyls' in the USA. Yes the car be be off the road for a while and it won't be cheap but once all the work is done on the ECU and refitted to the car there won't be any chance of the ECU Capacitor issues and there's no need to mess with the immobiliser. I decided this after talking to Bill (Lscowboyls) about the whole thing and what's involved replacing the capacitors. I should have done this in the first place but you live and learn.................... It's more complicated on the 97-2000 VVTi LS400 ECU (apart from the immobiliser thing) for a few reasons, if anyone want's to know the ins and outs of it all then pm me and I'll do my best to explain. If you're thinking of attempting this yourself on any of the LS400 ECU's, my advice is................don't do it and have it done by an expert who knows what's involved, not just electronics soldering but an experienced expert in rebuilding ECU's with this issue, i.e. 'Lscowboyls' as mentioned above. I will continue working on the immobiliser thing on the spare ECU to see if I can reset it or disable it and also continue working on the mileage adjustment on the instrument cluster.

Update on this and it’s not good news. Cloning the immobiliser key data from one ECU to the other hasn’t happened yet, more involved than I first thought but I will keep at it. I then thought I’ll replace all the caps, not as simple as I thought. I struggled to remove the caps in the first place, done this in the past although it was over 30 years ago. I tried all sorts, iron temp, solder, flux, solder sucker and every trick I could think of but still struggled. I replaced 4 caps eventually and removed 1 but then decided to stop. I was either doing something really really wrong or I’m just too old now or don’t have the skill anymore or all three🙄 I since found out that the 97-2000 VVTi ECU is more difficult to work on than the earlier ones, more difficult removing components apparently and is more sensitive to being worked on. Maybe that’s why I struggled. On the up side I found a company willing to replace the caps, ATC Drivetrain in Cannock. I saw this company on Car SOS the other day, 90’s MR2 with an ECU issue and needed a new IC and capacitors. ATC tested it, diagnosed and repaired. They can’t do the same with an LS400 ECU but are willing to replace the caps if supplied.

To quote the website 'Some bushes is only available in 90ShA hardness (yellow) because the original rubber bushes is made of a hard rubber compound.' That is probably true because I noticed a difference in the hardness between the rubber bushes when I replaced all the suspension on my car with OEM arms/bushes, I checked the stuff I took off to see if they were cracked or split and noticed it. For example, the front strut bushes are/were softer than the front lower arm bushes which were in great condition.

Looks to be decent stuff. New arms from Amayama are £280 delivered plus import duty etc. of approx. £68 - total £350 plus the parcel force admin fee of £12 (I think) so all in around £360 - £370. Not far off double the price of the aftermarket bushes and ball joints, £190 by my reckoning.