I have heard many different ways to reset the ECU and was wondering if they all work or if there is really only 1 way to reset it.

1. Disconnect the battery for like 10 min., then go drive real hard.
2. In the MKIV tech articles, they say that u can reset the ECU of a Supra by taking out one of the fuses. Can u do this w/ the SC?
3. Drive around hard for a week w/ the ECT switch on all the time.

 

I've read on this forum, if I'm recalling correctly it was 20 min. The method used was disconnecting the battery.

As for driving hard, the ecu is self adjusting to driver's style. So I'm assuming that would by correct to a point.

 

Sorry, I'm an idiot... what is an ECU and why would you want to reset it? Does it damage the car in any way?

 

ECU- Electronic Control Unit
The ECU I am referring to controls gear shift, etc. The ECU is programmed from the factory for more economical driving habits. When reset, if u drive hard, it remembers this driving pattern instead of the more economical pattern. Therefore, when u press the gas it thinks u r going to floor it so it does it for u in a way. In laymen terms....u won't need to floor it every time the light turns green.
This isn't the only ECU...steering,etc. The steering ECU controls the sensitivity and feedback from steering. Many people in the GS forum have gotten the steering upgrade from L-tuned which makes the steering more responsive (I think) like the BMW's. Look under ECU101 on the CL homepage.
It doesn't damage ur car.

 

Disconnecting my battery for over 20 minutes: This worked GREAT!!! My car actually felt SO much quicker, it didn't feel nearly as sluggish as before and the car loved to stay in it's powerband.

Removing the fuses for 20 minutes: Well, I removed the ECU A and ECU B and IGN fuses (just to be sure) for about 1 hour. I can't really say that the car felt as good as disconnecting the battery for 20 minutes, it drove somewhat better, but nowhere near as good as removing the battery.

 

How do u go about disconnecting the battery?????? I know that u disconnect the neg. (ground) wire 1st, but i think there was an earlier post on this forum about disconnecting the battery and the electronic key being messed up. I have a 92 SC300. Do i need to worry about the key being reprogrammed, etc. or does that just apply to newer SC's? The thread kinda scared me and made me not want to disconnect the battery ever.

 

I think resting the ECU will work for a whle,but another person told me it will eventually go back to its orignal agressivenise,that's why i have not tried it.


So you rest it and just floor it the first time you take it out?You only have to do this once right?

Have you guys heard of it resting itself when you have just programed it to learn your agressive driving habits?

 

i believe u have to drive it hard for a while...not like 2 hrs. but i would imagine something like as much as u can for 2 days after u reset it. Someone who has done it would know better than i do

 

No need to disconnect the battery, just open the main fuse box right next to the battery and pull the fuse marked EC1 ( I think), should be 30amp, for a few seconds.

 

There are many electronic bits that can be reset just by pulling the relevant fuse for a few minutes, the fuel ECU being one off them, but I am assured there is a lot of trickery built into the ECU which is well hidden.

We found with trackday settings (altered boost settings & stiffened TEMS suspension) the battery needed to be disconnected for some time (overnight certainly does the trick), follwed by some spirited driving to allow the system to "re-learn" your driving style.

 

I disconnected the battery for about 5 mins and plugged in the trackday settings jumper and wired it inside the cabin, and I'm definitely sure that the trackday settings are on. Revs higher, more torque, better gearchanges and response... all from 1 jumper. As you can tell it's always on now. I drove it hard for about 1 hour, Kinglake mountain track uphill chasing a worked Skyline R32 GTS-T.

I dont know of the trackday settings will work on the US models, as I dont know if they have the same diagnostics port....

anyways... back to the topic... pulling the battery usually does the trick... while you have that harness out... change the ground cable cos it's too narrow....

Toan

 

Hi Toan - how you doing?

Several guys who tried the Trackday mod reported some strange affects depending on the amount of time the dropped the battery power, so I leave mine off overnight.

As the V8 dont have turbo's the boost settings are immaterial but I believe they can get the suspension settings with the diag jumper in place, only on TEMS/Active suspension obviously.

Like most, I just left the jumper in place and use the ETC switch to change from Fast to V/Fast.

 

MyLexusSC300
Yes by disconnecting the battery you have to reprogramm the infrared key after a while.
But its very simple.
I´ve found this at another Lexus SC Forum some months ago:
Step1: Open drivers door."Using the door lock control switch, perform "lock,unlock" operation 10 times with in 30 seconds.
Step2: Soon (less than 2sec.) after performing Step 1 continue to press the transmitter switch for 10 seconds.
Thats it.
I tried it out after changing the timing belt.
The funny thing: It worked, but I have to sit IN the car with the door CLOSED.

 

@MyLexusSC300
Yes by disconnecting the battery you have to reprogramm the infrared key after a while.
But its very simple.
I´ve found this at another Lexus SC Forum some months ago:
Step1: Open drivers door."Using the door lock control switch, perform "lock,unlock" operation 10 times with in 30 seconds.
Step2: Soon (less than 2sec.) after performing Step 1 continue to press the transmitter switch for 10 seconds.
Thats it.
I tried it out after changing the timing belt in Jan.2001.
The funny thing: It worked, but I have to sit IN the car with the door CLOSED.

 

I believe the trackday settings also adjusted the steering response for V8 onwers as well and the Transmission gearing a little harder.

One of the V8 owners posted somewhere (I forgot) that the steering was too responsive for his liking, too much feedback, so he turned it off during normal driving, but turned it on during winter/snow so that he could get more handling from the road. I'm not sure though. He mentioned that on the V8 the jumpers were different in the diagnostics port, and he couldnt remember which ones they were. I also believe he had a US spec SC as well.

Toan