LS 430 ECU repair

Sent in my ECU for repair. I had a hard shift from 2nd to 1st when coming to a stop. So much so I thought the brakes were sticking.

It was a 2 week turnaround including the Thanksgiving holiday so I thought response time by the Ebay seller was excellent.

The removal and installation of the ECU was very easy. I've included the ECU locations for the LS 430. The ECU I sent is located under the hood and noted as the Engine Control Module.

Happy to report that the hard shifting is gone.

 

What was the nature of the repair? Did you have it diagnosed as an ECU failure? If so, was it leaking capacitors or something else?

 

Don't know how they repaired it. My diagnosis consisted of it's a transmission issue and I would rather risk $130 to repair ECU than to put in a new transmission. Also there have been other posters who have had the same repair with great success to shifting issues.

 

It has been said that the shifting issue comes from cracked solder joints I think mainly on the larger surface mount resistors. GM clusters have problems with solder joints cracking on the large resistors so it's not just a Toyota/Lexus problem.

 

I've often wondered what is fixed in these ECUs when they get sent in. I do PCB component troubleshooting and repair (discrete and SMD) for a living so I've always wanted to have a look and see just what needs done and how hard it is to do. Might end up getting a spare computer that is having problems and opening it up to see for myself.

 

You would probably enjoy watching this, rav4 but should be the same for the LS.

 

Wow, if that's all it takes that's insanely easy, just basic run-of-the-mill reflow work. Now I really do want to get a spare ECU and try it out. I had a 1994 ES300 that I recapped the ECU in due to leaking capacitors, it's now my Mom's car and still working well after almost 280k miles.

 

Hi. Where did you get your ECU repaired? I have the exactly same problem as what you had discussed here on my LS 430.

 

Hmm... this is good to know in case I start having issues. Thanks!

 

SIA electronics, also this listing https://www.ebay.com/itm/Lexus-LS430...72.m2749.l2649

 

My 93 SC300 just started having ECU problems, at least I think that is the cause. It randomly shows 100 mph speed and then returns to normal, cycling back and forth as I drive. I have read that is one sign of needing my ECU recapped.

 

Those LS430s that have the ECU in the engine compartment room suffer the soldering crack issue due to the extreme heat cycle. On the other hand, following models suffer the failing electrolytic capacitors problem since the internal liquid QAS (Quaternary Ammonium Salt) which becomes very strong alkali when aged and the corroded lead wire expands the rubber seal and the liquid leaks out. The PH of it is often higher than 10 and copper traces are easily eaten and damaged. All you have to do is to replace those capacitors before traces are damaged. I remember there are some SC300 owners posting their experience at some where here.

● Lexus LS400 - 1990-2000 (in 1997 and earlier models, the problem is extremely common)
● Lexus SC300 - 1993-2000
● Lexus SC400 - 1992-2000
● Lexus GS300 - 1993-1996

● Toyota Celica GT - 1985 -1998
● Toyota Supra Mark III (JDM) - 1986-1993
● Toyota Supra GT - 1995-1997
● Toyota Supra Mark IV - 1993-2002
● Toyota Supra Twin Turbo - 1993-2002
● Toyota MR2 - 1990-1999
● Toyota Camry - 1987-2001
● Toyota Soarer - 1992-2000
● Toyota Aristo - 1993-1996
● Toyota Celsior - 1990-2000

I searched and found these.
https://www.clublexus.com/forums/ls-...l#post10467228
https://www.clublexus.com/forums/ls-...l#post10955248