Hi All,
The issue I'm having with my wifes car is when slowing down at around 8mph the car hard shifts from 2nd to 1st and I do mean HARD, anyone have this issue before and hopefully a fix for it?. The car went into the shop for this problem and needless to say and 4grand later, it's in my garage and Not fixed !. My current thought is it might be the high pressure solenoid in the transmission ?
it's a 2006 IS250 RWD with Automatic Trans.
Thanks
Brian

 

What exactly did they do for $4k?

 

Best guess is tranny replacement

 

slicer1959,
My 07 250 does the same. Changed tranny and same result. With my research I think this will be the fix.
https://www.ebay.com/itm/324129819038
https://siaelec.com/product/lexus-gs...repair-return/

 

Is this reprogramming or PCB baking?

 

4K and still have the same problem?! The car should be back at the shop, or give you your money back.

Please add more info; how many miles on the transmission, any service done to the transmission etc? if any

 

A broken or bad Transmission or engine mount will do that too. It can feel like it a major transmission problem.

 

For the 4grand they replaced the ABS accuator, 2 calipers, bled the entire brake system, and did a partial diagnostics, for a problem they thought it to be !.instead of running full system check as standard practice and finding what the real problem was !.

 

most likely not a broken mount when the issue occurs at exactly 8mph everytime when slowing.and only the 2-1 downshift.

 

I;m not sure.
Try searching the GS forums. there is some info there.

 

It can do that exactly. You should have then all checked. Its even hard to see the broken rubber sometimes till it is taken off. They can they to pry move it and see how it moves.

 

Did said shop even flush/drain the trans fluid and refill? Did they test any of the shift solenoids within the trans? Sounds like they fixed other things, but nothing having to do with the actual issue mentioned here.

 

+1 on the solenoid ^

 

Ok, well until I get a new #1 solenoid for the trans, I decided to reset the ECM and see if that would gain a little more time and miles, after pulling the ects and efi fuses then putting them back in, it did what was expected, not start on 1st try or 2nd and then started fine on 3rd, but now and bear with me......now its as though the throtlle isn't working anymore. Not sure if there is a step i missed or is it that now the throttle needs to be reset, it's moves just a hair when pressed and by hair I mean from idle to 1000rpms and thats it !
So I could really use some input on solving this.........and a cold beer! lmao!
Thanks All.

 

Discount the battery, clean all the connections, and plug and unplug everything you can get your hands on. Also look for rodent poop incase someone got to your wires.

ECM container has like 12 or 14, TB, injector driver, and maybe the trans connector.

When it started, did the idle go to 1500? Did you eve put it in reverse or drive?