So I started up my car and drove it to the post office on Monday, driving there was fine until I made it exactly to the post office. As I was pulling in I notice that when my car was down shifting to the lower gears it started Jerking the car and when it hits 1st gear the whole car hops. Drove it home from work Saturday night after work and let the car park all day sunday and then went to the post office on Monday morning; that's when the problem started to kick in (NO CEL). ⚠️HELP ME PLS!!!!!!⚠️

 

Very common problem with the 04 and newer 6 speed ls430. You can send your ecu to SIA electronics tell them you are having transmission shifting problems. Search here on the forum there are a few threads about this problem.

https://siaelec.com/product/lexus-ls...repair-return/

 

The ls430 shares the same ECU/ECM as the ls400?

 

No, it doesn't.

 

Oh, but how come the ecu says 1uzfe? But the description says Lexus Ls430 ECM ECU Repair & Return Service

 

​​​​​​ If you already know it all why are you on this site asking for help? They are different ecm's and the 1uz had it's own set of problems. Your rude question would be better asked of the people you could pay to fix your current problem.

 

I don't know it all, I'm not being rude. I'm just asking cause the picture has a ecu with 1uzfe sticker on it but mine is a 3uzfe and what I've been told and seen is the ecu being corrupted. If anyone is being rude it's you.
all I want is for my car to be back up and running like a lexus, dunno what I said to have trigger you but I guess I'll just apologize 🤷‍♂️

 

Why don't you ask that company about the reason why? I wouldn't trust the company which confuses the customer.

 

The solder used by Denso/Toyota on the late UCF30/31's printed circuit board was a “lead free” tin alloy called Sn-Ag-Cu (“SAC”). It causes solder cracks or cold solders more often compared with the older lead containing solder. This problem sometimes causes the shifting and other problems, I must add. A person who is good at finding those points would fix the ECU all by him/her self. All you need are your good eyes and soldering skills/tools.

 

Not corrupt just like Yamae said broken solder joints. BTW you can call it a Lexus but really it's just a Toyota Celsior with an L on it and some numbers to compete with German luxury cars.

 

I think SIA say somewhere on their site that the images used are just placeholders - check the other threads on this forum with their work and most people seem happy (haven't done it myself).

 

Another LS owner was asking the same question and coast. On ebay, I found SIA will repair your ECU for $115 as opposed to $185 listed. Had mine done for the same issue and now it drives better then when I bought it, I swear.

God luck

 

Hi guys,

I had the hard down shifting as well on my 2005 lexus ls430 with 206k miles. Went to a shop to have it looked at and they didn't know what was going on. Said it might be the shift solenoid. They sent it to a transmission shop who tried to do something with the ecu. Either flash it or reprogram? Not quite sure. Both parties did not know what was going on. They both recommend me get rid of the car rather than dump money into it. I read on here to send the ecu to sia electronics. Sia electronics wants you to explain what is going on with the car and include that in the package with your phone number etc. They fixed the problem right away and the car has never shifted better. If you are having this issue, I highly recommend sending the ecu to them first. When they received the ecu in the mail, I had it back within the week. Cost $190 after taxes including the return shipping. I did pay about $12-$15 to ship it to them so overall out of pocket was about $205.

Tim

 

Fortunately, this topic has been discussed a lot. My experience is most shops don't know what to do. I got enough improvement with having a full transmission servicing and an old Toyota Service Bulletin performed to make me happy, but some day maybe I will pursue the soldering.
This is a long read, but probably the most definitive thread on the topic:
https://www.clublexus.com/forums/ls-...mission-2.html

 

Im so grateful places like SIA exist to help keep our LS430s on the road.