jubin

ls 430 2004 model gulf spec vehicle has developed a jerky and shaky downshift(3-2&2-1).
many technicians tell me this is because of a faulty ecu
i have only one option of getting an old ecu since new ecu is too expensive.
but the challenge here is i get a japan right hand drive vehicle's ecu ,of the same model but my technicians say we need to do some remapping of the used ecu to suit my car & to do this they are gonna charge me high.
please can anyone out there help me with this issue.

tallcaguy

Ay dealer (and some indies) can "reflash" (meaning reprogram) the ECU that controls shifting. This is a standard problem for this year transmission.

Maskvich

Hi Tallguy,

Can you expand a little on the common problem with 2004 rough transmission shifts? I have owned my LS430 for about a month now with 94k miles and noticed the transmission upshifts roughly at times or stays in gear a bit longer and results in a jerky acceleration when applying light throttle. Hoping this can be resolved with a ECU flash (and eventually a trans fluid change).

Thank you!

Johnhav430

I've owned my car since 81k, and it's now near 95k and had 3 drain/fills........I think there is a certain light acceleration scenario where the car decides not to stay in 3rd and goes back to 2nd. I've always assumed that's just the car, meaning although it's not underpowered, it still has to follow some algorithm when shifting, and pressing lightly on the throttle causes the above imho (as if it wanted to get into 3rd earlier than later, but now the rpms were not advancing as it had thought and needs to go back to 2nd)....meaning stepping on hit harder, the above shift doesn't happen, just continues on....my .02

Daspyda

iTrader: (1)

Your ECM needs to have the TSB applied related to transmission shifts. It cost me about $275 at the dealer - only they have the required computer.

Or, try putting it into "SNOW" mode to see if that gives you smoother shifts at low RPMs.

tallcaguy

My indy did the reflash for 100. The combo of reflash and multiple D/F's solved the problem. Now smooth.

tallcaguy

Interesting. After fixes, mine shifts smoothly and reliably. Doesn't make any difference if it's light acceleration or full power.

Johnhav430

I'm thinking a car is a car (this vehicle has plenty of torque at x rpm), meaning, if you press the gas too lightly and suddenly you're heading uphill, without more gas applied, the vehicle needs to go into a lower gear...this is why I'd rather just have a clutch and not let the vehicle decide....

tallcaguy

Agree. Miss my truck. If you decide to add a clutch and short throw 6 speed (or just paddle shifters) to your LS, please report and post pix

jayclapp

Lexus knew that their intended customers would not be interested in stick shift. That is why it was not even offered (much less considered) as an option. Those that want otherwise now should look at other cars.

Johnhav430

I tested myself and I am literally driving as if there's an egg between my foot and the accelerator, if I don't do that, the car doesn't have the 2-3 back to 2 thing.....it's a shame what's happened to the manual transmission. In a modern truck fleet, 90% of the new tractors are automatics. The old timers (35 and up lol) shake their heads and tell stories of how they didn't even need a clutch to change gears.

If there's still a place you can go and see vehicles with clutches, it would likely be third world countries, and Europe too.

k7q

iTrader: (37)

Same thing happen to my 05'
There's a tsb for it. TC 006-04. You can try that first. I took mines to the dealer to do the tsb, but same problem. Then they said to change the ecu. I paid $1800 for a new ecu. Now it's running normal now.