I'm thinking about having my ECM rebuilt, more of a precaution than anything else. I've read that SIA Electronics is a place a lot of people have used. Are there any other reputable shops for this?
Thanks!

 

Check out 400Fanboy's recent post in the 1st and 2nd gen forum about his experience with SIA. A tale of woe.
https://www.clublexus.com/forums/ls-...ed-my-car.html

 

I would suggest not to proactively have it repaired as it might come back with a problem. Mine is a 2001 with 187k and never a problem.

 

I'm not sure that I would do it on a proactive basis. They do not rebuild the entire unit, only the parts that affect your problem and other common problems. If it's not broke, don't fix it. That said, I used and recommend Relentless in suburban Dallas. If you contact the owner, he may have an opinion that he will be happy to share.

 

Captain Obvious here -

This is a must read along with the 400Fanboy thread: https://www.clublexus.com/forums/ls-...capacitor.html

This is not to say it doesn't happen; it wouldn't hurt to be proactive and take a look for the start of leakage. But this too has associated risks - ESD discharge, pin connector damage, etc.

I don't believe capacitor issues plague the '98 - up model years like the 1990-1997's. If there ever was a, "don't fix it if it ain't broke", this is one of them.

Picking the right vendor to do the work is also important.

 

I reached out to him before and I got the impression that he does good work, just didn't seem to be in a hurry to prioritize anything. Like, I need to MINIMIZE downtime. Oh well.

https://www.ebay.com/itm/116157858115 this person also does the service.

But yeah, if it ain't broke, don't fix it in this scenario. I like to be proactive in the maintenance approach to my car but with this, not so much.

 

It may depend on his mood. He turned mine around in 24 hours. Overnighted on a Monday on the way to the airport, I received it back on Friday when I returned. I was out of town for the week so no downtime.

 

Someone here recommended this place
https://stores.digitalautotech.com/l...epair-service/

I want to send my ECU in too because everytime time I reset the ECU the car feels peppy. Then a few days later it feels lazy. I contacted the eBay guy and he was very responsive and he said:
Harsh downshift is the most common issue in that computer. It’s hard to say if a rebuild will fix your problem or not, but it can correct other issues. When you’re doing a reset it has to go through and learn adaptive. It sounds like it’s just learning something each time, it’s not a bad idea to get the computer done because it will fail in the downshift area

The eBay guy has the best price out of SIA, relentless and DAT.

I might bite the bullet and take my ECU to DAT since they are only 5 hours away from me.

 

There is nothing wrong with the ECU. These cars have always been terrible about trying to learn driving habits and make the car feel sluggish after awhile. Pulling the fuse or battery disconnect resets the ECU to start over and feel peppy.

 

I'm going to take the advice of everyone here and not mess with it, proactively. Like everyone here says if it ain't broke don't fix it.

 

I’m considering a ECM rebuild, but for a very different reason. I’ve tried every possible route to fix the check vsc issue - including replacing the solenoid. No matter what, once I hit the parameters for the error (50+ mph and 2 occurrences from key off to key on) it always comes back.

in the history of the vehicle, I can see it started occurring after the factory recall of the transmission caused the owner to replace. So, I think it MUST be the computer. I hate to do it being proactive and risk messing up other stuff but in my case it seems worth it?

 

Thanks to this member RomanNOVA for the eBay posting ECU rebuild, I have 2005 LS430 with only 137k+ miles and a few weeks back the tranny start doing the 3-2 harsh and 2-1 shocking violent down shifting, this person fixed or rebuilt the ECU within 1 week of turnaround time, the car is happily back on the road again. The transmission shift pattern now is better than the day I owned this car since 2016, the downshifting pattern almost inexistence from any speed to 0 mph! No issue starting the vehicle after the rebuilt, 2 thumbs up for this seller.

Here is the listing on eBay. Lexus LS430 ECU computer Rebuild service 04-06 Harsh transmission shift | eBay

 

In the LS430 ECUs the problem is not the capacitors, it's the lead-free solder that was used.
That 1st generation lead-free solder gets brittle with age and cracks causing weird and often intermittent issues.
Many of the ECU repair companies reflow the solder joints with better quality solder and most of the time that fixes the problem.
The good places will have an ECU test jig and will test it fully after reflowing to see if there are any other issues.