Update - Got my car back from dealer, removed the ECU and shipped it off to SIA. Should have it back next week.

 

Wait, are you able to drive without the ecu in place? Am I misunderstanding?

 

No, my car is parked. Can't drive without the ECU ... and you were right, removing it was super easy!! thanks for the advice.

 

I asked SIA if they could tell if the ECU was good. I haven't sent mine in yet because I am getting some work done on the LS 430.
They will charge $89 diagnostic fee if ECU is good.

 

Received the ECU back, and drove car around today a bit. Hard shifting is completely gone, and car drives perfect, just like it did before.
Going to take it out tomorrow for a small road trip, will post again with update.

 

It's a miracle? What magic do they posses.

Seriously, not only did my car shift like butter and continue to do so some three weeks later, but it drove (honest to you know who), better. Noticeably better.

Glad you got it back and whatever voodoo they do, works.

I wonder if I had done this first if I wouldn't of had to replace a stuck b solenoid? Oh well,

 

Yes! It's awesome. SIA is fantastic. I had a good feeling about it, but of course in the back of my mind I thought this is to good to be true. This forum helped big time !!

 

My 2004 LS430 165K miles just started having a problem when the car is stopping at a light or stop sign. It appears the tranny is downshifting hard from 2nd to 1st gear, almost like it jerks forward when stopping. The reason I think it is the tranny because when I put the car in first gear and come to a stop, it is fine. The tranny seems to be shifting fine through the rest of the gears. This just happened suddenly the other day without warning. I brought it to the dealer and they said I need a remanufactured tranny for $8300, they don't repair the your existing tranny. I'm sick and don't have $8300 to fix it. Is there some way to know upfront if it is an ECU problem vs the tranny itself? I'm prepared to buy a remanufactured ECU online for $650 if I know it will work. OEM number shown below, Or perhaps the SAI route is a much better option. About 10 years ago I took my car to the dealer for a TSB and they did an ECU reflash for unsmooth tranny upshifting from a low speed and it fixed that problem. Although this is a different tranny issue, I'm thinking this problem could be an ECU issue and not the tranny gears.

Engine Control Module - Lexus (89661-50693-84).

When using a scanning tool should any codes come up? Thank you in advance for your answer

 

For the 2004 LS430 hard downshift problem, do you know if a scanning code comes up? Also, if I by a remanufactured unit off the shelf and have it programmed to my VIN number, is it plug and play? Or is having mine rebuilt a better option?

 

Yesterday, June 8, I decided to ship the part to SIA for repair. This way I get my original unit back and don't need to do the extra programming. I am wondering about reinstalling my ECU once I get it back. Do I simply plug it in, tighter the bolts and start the car? Or are there some other steps that I need to take?

 

I think SIA is the best option because they use your OEM computer. the only downside is you are car-less for about a week.