avhart

HELP!

Hi there folks (especially Yamae) I have just received my 'repaired' ECU 89661-50170 from The US and its still not starting the car! Now I have found an ECU on Ebay with the number 89661-50160 from the UK. Can anybody tell me if they think this one will work?

I am beginning to feel that maybe I'll never be able to get this car running again!

Thanks in advance to anybody
Anthony

avhart

Nobody? Come on guys somebody out there MUST know something! Make an effort please ok?

JohnAndic

I'd buy another LS400 if I was you. See if your fixed ECU will work on that one.

LeX2K

I could not find any good info on those numbers. 89661-50160 could have been replaced by 89661-50170 but cannot confirm. What makes you think the ECU is causing a no start condition? Provide details.

avhart

Hi. Well the simple answer is because another ECU is starting the car and working fine. The guys in the US told me they installed the repaired ECU in a vehicle there and it worked normally with no errors so I have been thinking that they must have used an LS 400 to do the check which would have different parameters to my Celsior and that may explain why its not working in my car.

The car seems to want to start with it but never gets to actually run and the OBD gives error 41 which is the TPS signal but of course, nothing is wrong with the TPS itself because the other ECU is working great. Any ideas where I can go from here?

Thanks
Anthony

avhart

I would love to take your advice and buy another car but unfortunately its out of the question due to me not having the money to do that lol

Yamae

As far as I know, those upper 7 figures 89661-50 mean that the ECM/ECU is for models LS400/Celsior. Every LS400/Celsior's ECM/ECU has numbers 89661-50XYZ. Three digits after 50, I mean the last 3 digits
X indicates design level,
Y indicates market,
Z indicates the level of minor design change.

So, 89661-50160 and 89661-50170 are the same design level and the minor design change level is the same but the market is totally different. 89661-50160 is designed to meet with UK's regulations and the gasoline octane value there. Celsors use a hydraulic fan and the ECU is designed to control it. Those two are not fully compatible but similar some. Sorry that I only can provide you only this much of information.

avhart

Hi Yamae,

Thank you for that excellent additional information. I really didn't have the best luck when I bought that Celsior!

Now I know I have asked this before but with your vast experience would you be able to recommend a place where I can get my ECU repaired? Or at worst suggest a substitute number even if it means changing the hydraulic fan to an electric one?

You see, Yamae, any decision i make regarding that ECU is going to cost me money and I am not the type to just throw money behind a problem without a certain level of comfort that its going to work. You have a whole lot more experience in this field so I would be willing to blindly take your advice if you are willing to give it without holding you in any way responsible for the outcome. Also where I live in Trinidad and Tobago this must be the only Celsior in the country and the quality of the mechanics here leave a lot to be desired. So basically I'm on my own.

I hope you understand my predicament. Thank you very much indeed for all your help.

Anthony

Yamae

I understand your predicament since there were similar people like you even here in Japan. But all those Japanese old Celsior UCF10/11 owners are not there any more due to many restrictions such as ridiculously expensive 2 different taxes, no parts availability, high maintenance costs, frequent troubles and etc. Also they can't find good mechanics who can fix problems.

I don't know any good ECU repairing companies here except the company Nippon Denso. Problem is that they don't accept any personal request. As a volunteer, I used to fix ECUs and others requested by local shop owners and dealer managers but I only did those with the car together. When I do it, I make it a rule to confirm the problem myself analyzing precisely using measuring equipments on the car and after fixing, I confirm that the problem is completely solved. Sorry to say, but I don't fully trust most of mechanics to analyze electronics related problems.

Regarding the ECU 89661-50170, it is OK to use 89661-50171 according to the information post #12497 at Celsiorup.com. But the availability of it is also not high. Currently, this seller is selling it but quite expensive.
https://www.monotaro.com/p/1406/4296/

The hydraulic fan system makes some differences and non Celsior's ECUs are not fully compatible although most of other controls are similar if the manufacturing term matches. If I were you, I would make a hydraulic fan control circuit myself obtaining the temperature data from the ECU or an additional sensor after confirming an inexpensive ECU for a LS400 is OK to run the engine.

MattNXF

Take it to a dealership.

avhart

Sounds good in theory Matt but the dealership in my country wll not touch it.

avhart

Yamae, you are one in a million.

I should be able to make the hydraulic fan adjustments so my final request is to kindly ask you to recommend an LS400 ECU number that I can use to run the engine? I don't want to mess up by choosing one myself even with all the exciting new information you provided to me as my experience is very limited in this area.

Thank you very very much. I would hate to have to scrap the car after all the time and effort I have put into it.
Anthony

Yamae

Thank you for the complement, avhart. But I am just posting what I know for those who love LS400/Celsior trying to keep them running on the road.

I can not guarantee but following ECUs for USDM LS400 will probably be OK to run the engine although the hydraulic fan will not be controlled.
89661-50140 92/08-93/01 UCF10
89661-50141 93/01-93/08 UCF10
89661-50142 93/08-94/10 UCF10
89661-50150 92/08-93/01 UCF10 CALIFORNIA SPEC
89661-50151 93/01-94/01 UCF10 CALIFORNIA SPEC

The hydraulic fan needs the control voltage and the current to drive the liner solenoid which controls the hydraulic pump's power. I don't know how much of power is needed to control it. May be I need to get the data some more and study about it.

avhart

It is my pleasure to complement you Yamae because I very much appreciate all the time you take to answer my seemingly endless questions! Its good that we both have the same interests in keeping our old cars running however.

Thank you a whole lot for that advice on the substitute ECU numbers. I now have some concrete information that will allow me to work with more confidence.

I'll keep you and the forum informed of my progress.

Thank you and good luck in all your future endeavors and if there is ever anything I may be able to do to help you or any other Lexus owner please do not hesitate to ask.

Anthony

Yamae

I'm looking forward to see your success to revive your Celsior.

I have a service manual written in Japanese here but it's for Celsiors Gen 2 and Gen 2.5 (Manufactured between Oct. 1994 to Aug. 2000). In the manual, other than the ECU, there are only 2 parts which are related to control the hydraulic fan motor. As you see drawings below, one is a solenoid and the other is a temperature sensor attached to the radiator.

The specification of those are 7.5-8.5 ohms @ 20 degrees C and 1.48-1.58 k ohms @ 80 degrees C. I think these are similar to a Gen 1 but I have no idea to confirm since there are no Gen1 Celsiors any more here. Is it OK for you to measure yours? In case you can't measure the temperature sensor at 80 degrees C, it would be OK to measure it at ambient. It should be a few to several times bigger than 1.5 k ohms @ ambient. If those values are similar, I think I can provide you a way to control the solenoid using semiconductors. But to deal with semiconductors is not for every one, I know, and I'm thinking of an easier way to go. For an example, this type of PWM controller may be the one to use. I think it can be used with some modifications. But you have to be comfortable to use a circuit tester and a soldering iron at least. I think it is almost the MUST to handle those 2 to keep an old car.