I sent in my 2004 LS430 ECM to SIA and they received it today. Still having issues with the shifting after trans rebuild.
was wondering if you put in a 2005/06 ECM into a 2004 would the car run?
I did see another thread where someone said you can prep an ECM with a crossover wire.
Just wondering...
Thank you

 

Any six-speed ECU should work I have an extra if you're looking for one cheap. You need to program the ECU to match the immobilizer and key it's a simple jumper wire to the OBD2 port if you have questions PM me

 

Well good news - SIA called and our suspicions were correct - the transmission circuit was an issue and it's being sent back today -
Can't wait to put it back in the car..

 

Thx - got the unit repaired at SIA - will be interesting to get it back into the car.

 

pls update the thread when you get the ECU back !

 

What was the problem in the ecu? Leaking elect.capacitors?

I have been seeing a lot of posts regarding rough shifting/ECU problems. My ‘06 doesn’t have any drivability issues right now, but I wonder if I should have my ECU looked at for preventative measures?

is it inevitable that it will fail at some point in the near future due to its age?

 

If its not broke dont "fix" it, I have had 6 LS430's through the years and never had an issue with harsh shifts or any ecu troubles. If its not an issue dont make it one lol

 

I was told the transmission circuit was repaired and was an issue.
I also hear from older forum posts that the solder used at the factory can get compromised due to age and vibration and SIA checked the solder joints as well.
If it was as easy as resoldering solder joints that would be easy to fix - There is some reprogramming involved from what I was told as well.
Thats all I know about fixing an ECM/ECU

H.

 

Well good news - it's a 3 pointer all net, 4 aces & grand slam homer - So far so good.
Just go the ECM back from SIA at 1pm UPS.
Reinstalled ECM and took a test ride and got the car up to temp.
A few foot in the floor where applicable ( adults only here ) and she is buttery smooth.
Will update next week once I get the car back out on the big road.
So the hard morning shift didnt show up initially and the hesitation hunting for a gear on the uppers gears while rolling is gone.
So far it's rock solid
Had a chuckle after watching that other service guy on YT complain about his customers packaging - SIA put the ECM in a plastic UPS bag and sent it inside the regular small UPS express box.
No bubble wrap.

 

Both my LS's have this issue- where if you stop quick, then go to leave, the transmission smacks unless you wait a few seconds. https://www.clublexus.com/forums/ls-...-to-drive.html

 

Mine didn't have that symptom. Just hard bang into drive and it hunts for gears in the upper gears. The valve body is easy to inspect without tearning out the entire trans - mine had to be rebuilt in addition to the ECM/U -
My trans guy put a kit in mine. Plus the selenoids can be checked if the pan is dropped.

 

Glad to hear another SIA success story. It is a problem stemming from the no-lead solder that was required to be used. With no lead, the solder lines cracked over time. Same problem with the amp and the nav unit as mentioned in other threads. I have an 04 and have had to address it all. All fixed now and car is flawless.
I am no mechanic, but there are a lot of threads on this site about this topic, so I will summarize based on my reading and experience.
1. I agree with @05ls430518 above, if it ain't broke....but that is extraordinary you have never had to address it.
2. They will sometimes say this is a sealed transmission and never needs service. Yeah, but now they're 20 years old. Service it anyway. Always do that before further diagnosis.
3. These transmissions are notably strong. If you are experiencing a problem, assume it is electronic first. Actual mechanical problems are rare.
4. I have not yet done the SIA fix, but I did have an old Toyota Service Bulletin performed, TSB TC006-04 (attached), and it made a big difference. It isn't cheap, I think they charge 1.5 hrs of labor or something, but it was worth it.
5. This is a long read, but I believe it to be the authoritative thread on the transmission, and the solenoids are mentioned:
https://www.clublexus.com/forums/ls-...mission-3.html

 

I wonder if Lexus still offers the TSB TC006-04 service?

 

Jeepers, @funcrusher , living up to your name. We were having a good time here and you come with your doubt crap?!

I just had it done in 2022 at a Toyota dealer. There is some special instrument they need, but if you call and tell them the TSB and explain, they can verify if they can do it.

 

I remember asking Lexus about a transmission update and they were clueless, but I didn’t have the exact name and code