Remember,they haven't made them for almost 14 years.That coupled with all the customizing is making stock LS400's harder and harder to come by.

 

Well I know you said that you looked over all your traces and the boards very closely and that is good!

...but I would suggest taking a closer look at the capacitors. I also initially thought my board was 100% okay but then I took a very close look at the top of the capacitors and noticed that there was in fact a very small amount of leaking starting.

It is a very fine glossy film that will sit at the top of the capacitor and can be hard to spot. If a capacitor looses some of its electrolyte, the capacitance value WILL change. An electrolytic capacitor uses this fluid as one of the plates (remember a capacitor model is two parallel plate of charge) so in other words. ..... if the capacitor is leaking, it will screw up the capacitance value and possibly other stuff in the circuit and cause weird erratic issues.


Now with all that being said, I technically have not yet "graduated" since all my capacitors have yet to arrive in the mail!

I'll be sure to let everyone know if my issues are solved when I am done the capacitor replacement!

In the meantime, take a closer look at your caps.

 

my caps looked like new, no sigh of leaks or anything. But when I changed them, I immediately felt improvement in transmission work. Its worth doing it...its not hard and not expensive !

 

good job!

 

I've recorded my experience removing, repairing and installing the ECU in my 1996 LS400 in words and pictures. See the attached document for details.

A heartfelt thank you to all who came before me.

I've put hi-res photos of my work in my photo library. Club Lexus Forums > Photos > wicogen's Profile > Albums > ECU repair

Drive safe.

NB My first post, be gentle.

 

Welcome to Club Lexus!

very interesting story and write up!!

good job!

 

Many thanks for your detailed report with many photos. This is surely the another great write-up. Let me convert your Microsoft Words format to a PDF file so that everyone can read it.

 

if you have a 98-00 LS400 and have already ordered your capacitors from the recommended list, but not yet installed them, please note that the quantities and recommended types from Yamae and I have changed on the 47uF and 330uF caps in particular, so please compare the current recommendation in post #1 of this thread with what you have, and then you need to likely order a couple or three more caps to fill in.

 

Wow! I'm pretty sure this is what's wrong with my car! Hello everyone, I'm new to Club Lexus. I bought my mother-in-laws 96 ls400 about 2 months ago and it has been in the shop for a month. I picked it up from the mechanic today because he couldn't figure out what was wrong with it. I am going to try and check the ECU tomorrow(I'm not very mechanically inclined so wish me luck). I'm not too confident about changing the capacitors myself because I've never soldered anything before. I see on eBay there are a few people that rebuild these with lifetime warranties. What do you guys think about that? Do you think they use the correct capacitors? I know it's a bit pricier but I don't want to mess anything up. Or maybe I could try the procedure and if it doesn't work then send the unit to be rebuilt. Any feedback would be greatly appreciated, you guys have already helped me so much I'm almost certain this is the problem after reading all the symptoms. Thank you guys so much! It's been very frustrating because I absolutely love my new car and haven't been able to drive it nearly enough.

 

from what I read, that eBay guy doesnt use the right type of capacitors. Dont waste your money and time !
As far as soldering, I have soldered wires in my car, but I didnt touch the ECU, because those things are sooo small !! Dont do it if you never done it before!! Find someone who deals with electronics (repairing), and let him do the work.

 

this!

I have see the work of all of the ebay "rebuilders" and all of the craigslist "rebuilders" and all of the private firms on the Internet I can find, and sadly, none of them are using the right capacitors or doing this fix correctly! - you need to order the correct capacitors in post #1 and do it yourself or take them to a friend who is an expert solderer!

 

Yeah, it seemed a little sketch to me. Anyways thanks for your responses. I guess I'll figure something out, at least I know what the problem is now. Do y'all think it would be ok to drive it around town on a minimumal basis until I can find somebody to replace the caps? Do mechanics normally do this type of work? Thanks again for responses, this forum is truly a great tool for Lexus owners! Keep up the good work y'all! If there's anything I can do to help the cause let me know. I'll post pics when I get it fixed and cleaned up.

 

This is a really good stuff. I have 93LS with 134K miles on it. After reading through the whole thread, I have decided to replace all capacitors. I still do not have any serious problems relating to ECU other than sticking needles issues.

It took me couple of hours to read the whole thread. Great work and effort by LScowboy and Yamae. Not only bring the problem and solution to surface but keeping the support to help other owners for more than a year.

Another thing I have notice was that it seems that most of problem is being surfaced at hot climate, like Texas, Florida. It may be that the hot temperature in summer time is to blame. Even though mine is 93 model, issues have not surfaced yet And I live in mid-west.

I have place an order solely based on one of the posting who owns 93LS from Digi-Key and if either LScowboy or Yamae can verify that I have ordered the right capacitors, that would be greatly appreciated. Here is what I ordered through Digi-Key:

Quantity Part Number Description Quantity
2 P10316-ND CAP ALUM 10UF 50V 20% RADIAL 2
2 P10317-ND CAP ALUM 15UF 50V 20% RADIAL 2
1 EEU-FC2A470 CAP ALUM 47UF 100V 20% RADIAL 1
2 35ZLH100MEFC6.3X11 CAP ALUM 100UF 35V 20% RADIAL 2
1 EEU-TP1V221L CAP ALUM 220UF 35V 20% RADIAL 1

Thanks.

-- Mike

 

I don't like your 220uF choice, that is not really a high ripple, low ESR cap, more of a general purpose.

the rest of them will work

why did you not order the ones I recommended in post #1 (well the 100uF was the recommended one, so you did very good on that one). - the other 3 are Panasonic FC's, which are very good caps, but are just barely low ESR by today's standards, but they will work

 

LScowboy,

I called the Digi-Key Corporation and alter the order as follows:

- I kept the 100μF one.
- Others are changed to
Qty. 2 of 10μF - 50v Chemi-icon KZE EKZE500ELL100ME07D
Qty. 2 of 15μF - 35v Chemi-con KZE EKZE630ELL150ME11D (15μF-50V)
Qty. 1 of 47μF - 63v Panasonic FR EEU-FR1J470B
Qty. 2 of 100μF - 10v KEPT THIS
Qty. 1 of 220μF - 16v Chemi-con KZE EKZE500EKK221MJ16S (220μF-50V)

Please let me know if these will work better. Total cost of these capacitors are actually less then my previous order.