bcatv

Joined the forum to thank the originators of this thread, after putting >$2000 into my son's '95 LS400 with a decent local shop without fixing the problems, I spent 20 bucks mostly shipping with DigiKey and Mouser and a day relearning soldering to replace the caps (one had leaked and I feared some traces were gone, but went ahead as no loss), and car now running like a Japanese watch.
Thanks again LS and Yamae. Best of the net to you!

MensaPE

LScowboyLS, Thank you SO much for this information. I have several Gen 1 SC's, and your and Yamae's work helped me with finding my problems. I had Tanin repair 2 ECU's and SIA electronics another. I also find this problem in the Nakamichi power amplifiers. Thanks Again!!!!!!
ps: I don't know what the spoiler function is, and can't seem to get rid of it. Sumimasen!







MensaPE

MichaelPm, Tanin Autoelectronix charged me $180, seems to work fine.

Margate330

As someone who repairs high end foreign industrial electronics as part of my job I think that price is excellent.
The only way it can be done professionally & reliably at that price is if someone is set up for working on that exact item.

e1701b

Do you have to remove the screws that hold the lower board to the frame? I ask because mine have what looks like solder dripped into them. The only reason I see to remove them is to be able to get to the 47uf cap on the edge of the board sitting under the frame. Can the 47uF be replaced without removing the board from the frame?

Thanks for any help.

dhood

Hello LScowboyLS and Yamae, I'm in awe of this thread and the wealth of information you've so diligently provided. I've gotten into some trouble.
>>>> I'm in desperate need of at least one(1), or four(4), of the 47uF and at least one(1), or two(2), the 220uF<<<<
I had followed the recommended parts list and put the various items, and alternates, into my shopping cart at digikey. Sadly, I failed to confirm the order in time and 2 of the needed capacitors are now on backorder(at mouser, too). (I had only realized my error after wondering why the package hadn't arrived after 2 weeks) I have no clue as to how to identify what is, or is not, a" Low-ESR" capacitor. (and have failed at 'Google University' on this subject)
Could you please Help me identify alternatives?
Sincerely

Yamae

Don't worry, my friend. These should work.

47uF 63V
https://www.digikey.com/en/products/...6-3X11/3134467

220uF 16V
https://www.digikey.com/en/products/...6-3X11/3563156
https://www.digikey.com/en/products/...6-3X11/9553861
https://www.digikey.com/en/products/...1MF11D/3529147

Yamae

It has been a decade since LScowboy and I had talked on the phone discussing about the ECU failing problems and started a new thread. He said, "This gonna be a big thread". I never thought so but it actually was and there still come people and ask us. Unfortunately LScowboy is not here anymore and I have to do some instead of him.

A decade is long enough to change things and the availability of capacitors were also affected. The list we made is getting old and some of capacitors are not available or obsolete. There also started to sell newer capacitors by major capacitor manufacturers. There come people who still need to change capacitors saying that some capacitors are not available. This time I understood that 2 capacitors were not OK to purchase. If there are other capacitors like those, inform me.

It would be the best to make a totally new list but currently I am busy doing things a lot as a chairman of a local community leaders and a helper who is still often called by local auto shops and dealers. I happen to speak Spanish and English some and there come requests to help foreign people living around here too. COVID 19 sure made an old man to run. So if there are no availability problems of some particular capacitors, please let me know. I'll try to find alternative ones.

dhood

Thank you. Thank you. Thank YOU!

Yamae

You are welcome. It is my pleasure that your LS and other sisters live longer.
Since you informed me the availability issue, I just added those capacitors to the post #1's capacitors link list.

Nuro

Hello everybody,

I need to replace my SMD aluminum electrolyte capacitor in my ECU car with 35V 220uF. This capacitor is manufactured by Vishay. It is 150CRZ type. Data sheet is here. There are two types for my application which are one and two. One has higher ripple current than two (630 mA VS 409.5 mA). From this, I prefer the type one.

I tried to search in digikey and compare the same capacitors with the same voltage and capacitance. The vishay is the most expensive than the others. Why? Does it mean it has better quality? Rubycon here is better in lifetime and low impedance with lower price. Any other suggestions? Any suggestions will be appreciated.

sayow

I have a 98 LS400 with 102k miles and have recently had the following problems that I am thinking might be ECU cap related.

ODO recently reset from 102k to 3800 miles!! Given its a low mileage car already, this is concerning (not that I plan to ever sell this baby)

About half the time the RPM gauge reads high and inaccurate (like 5k rpm at idle, redlined at highway speeds)

The same for MPH, reads about 3x the correct speed (although it is hilarious to do 65 and have it read 160mph

AC has developed a whine that increases with RPM and is only cool (no longer cold)

Shifting from 1st to 2nd is a tad delayed, no other performance issues car runs amazingly otherwise.

I am reading through this thread that 98-00 LS400s do not often have the ECU cap problem. Is that correct?

Finally, I really have no desire or skill to perform the cap replacement so what are my options? Ideally I would prefer to pay someone locally to do the whole thing (Kansas City area) or alternatively I can try and remove the ECU and send it off. Who is the trusted and preferred clublexus ECU repair vendor?

Thank you.

Yamae

See the diagram below and you will find how the speedometer works.
The main ECU is only getting the result of the calculation.

Using an oscilloscope or a pulse counter I'd observe the speed signal line coming from the ABS & TRC & VSC computer to the cluster unit first before jumping to the main ECU. When the pulses are OK, the speedometer/odometer problem must be related to the cluster unit. The ABS & TRC & VSC computer is averaging of 48 pulses from 4 ABS sensors and then divides the value and send the calculation result to the cluster unit.


Regarding to the delayed engagement from 1st to 2nd gear, I'd rather think it's not the ECU issue but the pressure issue or the clutch issue. If I were you, I'd do the pressure check first using an SST.

Adapter to check AT's line pressure

Anyway, your problems need to use measuring tools to find out the root cause(s).

dhood

I'm also attaching a picture of the repair done by a local repair shop. There were two broken/damaged leads and they were bypassed.

Aquat

My 93 ls400 (1uz) has been experiencing a hefty chunk of these issues i believed it was a simple short in the harness because some mice did a number on some wires so I electrical taped em to cover any exposed wires but the issues continued I engaged my parking break once and since that time the light has remained on this could be due to a break in the line (rear brakes have issues) but it would trigger with acceleration and turn off on breaking or coasting along with my tach reading 0 on idle but coming up with throttle when it works (could just need to be adjusted) and the speedometer reads about 10 slow again when it works could be the same as tach I'm also triggering my main o2 sensor and earlier today the reason why I'm here and seriously considering this could be my issue coming through my town I was experiencing the eradic idle and an extreme bog upon accelerating from a stop then on one stop i idled fine and got my chance to turn and it stalled out I was unable to start it for about 20 minutes I'd get 2-4 cylinders to fire once and it'd stop again so I pushed it to a parking spot waited and had to neutral start it and give it gas to keep it alive I limped it home through two foot using neutral to keep it revving until takeoff

i Know this was a long one just asking if anyone has had similar patterns caused by this issue