Any updates?

I'm curious to know what your codes are since you haven't mentioned that but only symptoms.

Try cleaning your MAF sensor first, cleaning dirty sensor fixed the issue for me.

I tried cleaning it with spray as well as with a qtip and alcohol. I did get a code p0761 for third gear shift solenoid but only one time.

The weird thing is that it doesn’t happen everyday. No consistency. It happens basically every other day and I never got another code. I just shut off the car, turn it back on and it’s perfectly fine.

Not sure if I mentioned but I had a drain and refill done at Toyota to make sure the level was fine. The car did not repeat the issue for the tech.

Thanks for the ideas guys. I appreciate it. If I can’t get this rectified I will be trading this thing in soon.

LexusDog, and progress on a solution? Or hopefully the fluid change was the remedy. As I stated, I had the tranny rebuilt when this occurred. So few posts about this issue suggests pretty bulletproof trannys on these LS 430s...

Hey, I sent the computer to SIA electronics and they supposedly rebuilt the transmission circuitry. Got it back today and put it in, and the same problem occurs.
It was nice of Sia to tell me that the ECM is most likely the problem.
Is your car a 2004 with the six speed transmission? And was it doing the same thing where it wouldn’t shift into fourth gear until you stopped and shut it off and turned it back on? Also what was the charge for the rebuild? Thank you for your feedback, it is tremendously appreciated.

Yes same 2004 with 6 speed transmission. Initially turning it off and back on was the work around but that stopped working pretty quickly. Rebuild was done at a local transmission shop about 4 years ago for $2,300 - $2,400 with warranty. All still working well now.

Thanks for the update. My car has been using the off/on method for the past 3 months and it seems to work every time. I guess yours didn’t last that long. I guess I will bite the bullet and do a trans rebuild.

Thank you for the circuit matrix. I had the ECM redone by SIA electronics and I also replaced the engine coolant temp sensor. I didn't replace it with a Toyota specific part and I do question if that could be an issue. As far as the shift solenoid, I do not have the space or time to be messing with that. From my extensive research on this subject, It seems that replacing all of the shift solenoids, the spider harness, and getting the fluid perfect doesn't always fix this issue. So instead of wasting time and money trying to replace parts, I will be replacing the transmission with a rebuilt or used unit.

One other thing that I would like to note for others that are having this issue, this is a very intermittent issue that doesn't happen everyday. What I have noticed is that if I drive it like an old man it tends to have the shifting issue first thing in the morning. If I drive it with more than 30% throttle, it seems to shift like a champ. Its almost like the car is saying to me, feed me some speed and I will do what you want. Lol

I have a 2005 Ls430 and will not shift out of 3rd. Code P0761.
I already drain and fill trans fluid. Changed filter. Fluid was not dark. Replaced the shift solenoid (S3). I sent out my ecu/tcm out to SIA electronics. They said they rebuilt the whole transmission circuit. It did fix the hard downshift I had when slowing down from 2nd to 1st but it still dosent shift out of 3rd. I tried the resetting by put key in turn to ON position and hold accelerator pedal down for 5 seconds. Key off and release pedal and wait 2 minutes. Did kot do anything. I disconnected battery for 30 mins and try again and nothing. I checked resistance on the ecu connector for solenoid s3 so I can check the wire all the way to the ECM. It's good 14 ohms resistance. Idk what else to do.

https://www.clublexus.com/forums/ls-...ttle-body.html
Try cleaning the air mix passages pointed out and discussed in this post. The issue with the transmission holding gears too long and rough shifting are sometimes found in the 1st and 2nd generation LS with the 4.0 L V8.

[QUOTE=lexusdog;10765335]Thank you very much for posting that link and information. I just ran out and picked up a new coolant temp sensor. I will put it in later today and see if the problem pops up again. It has only happened are a cold startup where the engine temp gauge is still buried



Is it worked

Did you ever figure out a solution?