I want to reset the ECU for the engine. How long do I have to leave the battery disconnected? I have heard anything from 1 minute to 10 hours. Does anybody know for sure?

 

I have heard that it take like 30min, but when I did it I left it unhooked for two days just in case. But this is just myth that it will adapt to new driving habits.

 

Supposedly (a lot of people keep saying), it does adapt to driving habits. But I'm not sure that the older generation Lexus cars do. Don't know because after my LS got serviced, it was all slow and wasn't responsive. But after a while of hard driving, it began to pick up and become more responsive.

 

The "adaptive logic" transmission wasn't introduced till the 98 model year. From what I've learned, the adaptive logic is always changing according to driving habits. If a "grandpa" type driver was driving your car for a little while, it will shift smoother and won't seem to accelerate as quickly. Hitting the gas hard a couple of times in a row will immediately change the driving response. There really isn't any need to disconnect the battery or ECU fuse to acquire the change.

 

Yeah, our 1999 LS400 has been "granpa'd" so it shifts very smoothly. But during a long period of hard-driving, it began to shift more aggresively and quickly.

 

spxchrome,

whoever told you disconnect the battery for 10 hours is an idiot and should be banned from ever giving car advice. once you lose power, the memory should be reset. give in fact that there are decoupling capacitors around the memory chip, the voltage should drain out pretty quick after u pull the battery terminal and thus, the memory chip loses power = loses memory. voila! that's all!