Rdrcr

^^^^
Very cool. Congrats!

Mike

FQS891

Awesome post!
Some of the links to the replacement caps have different voltage ratings than the original ones, dose this matter? Also. I have to do the caps in my 94 RZ Supra, which from memory has the same/similar values etc as the ones listed can I use these the caps in the links provided for this ecu too?

Rdrcr

I finally got around to removing my ECU to send it in for reconditioning. I'll be giving you folks a call tomorrow to place my order.

Mike

Yamae

Thanks for your report, L8274Jones.
It would be useful for those who are not yet changed, if you could write the details of the difference.

I'm suggesting people here to replace those QAS capacitors before the the leakage starts and copper traces are damaged. But some people are not good at soldering and hesitate to do the job.

Those aged QAS capacitors are not working properly any more causing too much ripples and signals from sensors are dirty and not processed properly. As the result, the engine doesn't run well and the AT doesn't shift smoothly.

DoktorYes

Replaced my caps a while back, to many "Good Things Happened" to list right now. Still in test faze! If you own a1994 LS400 do it as soon as Possible. You will be amazed!!!! Thanks to all, that suggested this fixx.

Rdrcr

^^^^
Nice. Good to know.

Mike

Ultramiler

I'm sorry if this has already been addressed somewhere in the 90 pages of this thread, but do you know if the ES300 ECUs suffer from the same problems or if the same faulty capacitors were used? I am specifically inquiring about a 1999 ES300. Thank you for sharing all of this great information, it seems like you have helped a lot of people.

Just FYI I have fixed many computer monitors by replacing bulging or ruptured capacitors on the power supply board. I also remember seeing a lot of bulging capacitors on CCTV DVR boards that at the time we deemed bad and non repairable.

Yamae

See inside of the ECU and check the ID mark of all electrolytic capacitors. If those are Nichicon PF(M) or PR(M), you'd better change those before the problem starts because those contain the QAS.

KarateDoc

I have a 95 SC400 that does not have any real issues but I figure I would open up the ECU (94 ECU) and replace the 8 capacitors. None of them were leaking and after I pulled them I checked them with a ESR meter. This is where I got the reference numbers

http://www.chemi-con.co.jp/cgi-bin/C...=p&pdfname=kze

Replaced the nichicons with Nippon Chemicon ones.

1993-94 SC400 needs 8 caps as follows:

Qty. 2 of 10μF - 50v
Qty. 2 of 15μF - 35v
Qty. 1 of 47μF - 63v
Qty. 2 of 100μF - 10v
Qty. 1 of 220μF - 16v

10μF tested at 2.47 and 2.34 Reference range was 0.5 - 1.5

15μF tested at .790 and .890 Reference range was 0.88 - 3.5

47μF tested at .304 Reference range was 0.17 - 0.66

100μF tested at .812 and .782 Reference range was 0.074 - 0.22

220μF tested at .235 Reference range was 0.42 - 0.12

You can clearly see that nearly all of the capacitors were out of range. Now I can be sure that there isn't going to be an issue with my ECU.

Rdrcr

My donor '93 LS400 ECU has proven that my intermittent tachometer issue wasn't caused by the ECU. I'm not sure if it a connection issue or an instrument cluster issue???

Regardless, I'm looking forward to installing the my original newly-rebuilt TaninAuto ECU.

Mike

Yamae

A 93-94 instrument cluster also has QAS capacitors inside and they are prone to fail. You'd better change them too. You can find more at below.
https://www.clublexus.com/forums/ls-...ml#post9461862

Rdrcr

Thanks Yamae!
I'll be sending the cluster to TaninAuto in the near future...

Got my ECU back from TaninAuto yesterday. I'm looking forward to installing it.

Mike

arnaudfabs

Hello,

I am about to order the caps for my 95 Lexus LS400 ECU, i just chatted online with a technician at Digikey as recommanded in the original post. After gaving him the info, he gave me 4 links. Can someone confirmed or not if they are all ok? It looks like it but i would like another opinion, thanks!

http://www.digikey.com/product-detai...9-1-ND/4333109

http://www.digikey.com/product-detai...2-1-ND/2650352

http://www.digikey.com/product-searc...0&pageSize=100

http://www.digikey.com/product-searc...0&pageSize=100

bdazzler

94 LS400

Having a major issue w/ loss of power, burning too rich, hesitant up hills, poor MPG compared to previous. I have changed out the ECU about 2 years ago using Auto Computer Exchange. Who knows if they used correct capacitors, maybe this is an ECU issue which is why I'm asking.

Has anyone had similar symptoms and it was the ECU?

Thanks in advance!

Mr.Gs_GTE

Hey guys, I am doing a 1uzfe w58 swap on a 94 Toyota pickup. After having the engine rebuild and installed it fired right up. At first I didn't have any check engine light but after running for 15 minutes the cel came on. I assumed it was because I still had the sub sensors disconnected and possibly because I had not yet soldered in the resistor considering I removed the egr system. So when I finally got ready to trace the ECU issues I jumped the diagnostic pins and I was unable up get the cel to flash. I thought I jumped the wrong terminals and I doubled check and found out I was in E1 and TE1, no ECU flashes/ in other words the ECU doesn't go into diagnostic mode. I did some research and found out the caps could cause this issue so I had all 8 of them replaced. Went to try that and I still have the same issue. The computer would not go into diagnostic mode. Is there something I am missing here? I've double checked my wiring and everything is adding up.
Issue: check engine light stays on at all times and won't blink when I jump E1 and TE1. Please give your thoughts as it will be very appreciated.