ACCHRM

Hi guys, I bought a 92 SC300 about a month ago, pretty cheap with mostly cosmetic stuff to be fixed. Its an auto, and the guy said that the ECU wasn't working good and he swapped it for a manual ecu and this is what its currently running. So I just put back the original auto ecu in it and went for a test drive, almost immediately started smoking bad and idling at about 400 rpm. Had to pull over and swap back the manual one(actually Im not sure if its manual, it doesnt say it anywhere and the size of the ecu itself is a little bigger). The problem that I have with the trans is that it wont shift to fourth. The only issue right now with the current M ECU is that when you step on it, it kinda dont know when to shift gears, and I really hope the ecu is the problem with no shifting to fourth. Trans runs pretty healthy and I dont think that I lost fourth, i hope its just the control unit. The main reason I put back the original auto ecu is that i wanted to see if it will shift to fourth, but it started smoking so soon that i havent got out of town yet. A couple of days ago i did a 5 h trip, and had to run at 4k rpm at 70mph, so you could say I burned a lot of precious fuel....Anyone else have similar problems? People told me that I need a a/t ecu with exactly the same number as the original one, the number is 89661-24310 and for now i havent found one yet

Ali SC3

iTrader: (10)

you can use any 92-95 sc300 automatic ecu and by the looks of your part number you want one that also has traction control. there are lots of them out there.
you could also potentially have a cali spec ecu originally but if you plug in a different type things should still work.
likely your other ecu is an auto one also, otherwise it wouldn't run the trans so well. there may be some that have trac control and some that don't as well
There is a large yellow or white sticker on the top of the ecu normally that says A/T for automatic transmission or M/T for manual transmission. if its missing it can be hard to tell.

sounds like your first ecu is bad, and not sure what the second ecu is. so find another one for sale that the seller knows is working is where I would start.
part number does not have to be exact same. just try and find a 92-95 with trac control (verify your car has trac control or get one without if you do not have it).

ACCHRM

these are both ECU's, the one that im running right now is the one that doesnt say anywhere for what trans is. My car doesnt have traction control. Do you think that the issue with fourth gear could be because of the ecu? PS the A/T is smaller in size with about an inch.

Duck05

Send them out to be rebuilt.... Try:

http://www.lexuspartsplus.com/home.html

He has rebuilt several member's ECUs with good reports....

Ali SC3

iTrader: (10)

Well the one on the top if you type it into google is clearly a gs300 93-95 ecu.
so its not for the same type of car even, likely that is the issue. it will run cause majority of the engine stuff is the same and ecu's have same connector, but not all the stuff is the same on both cars.

the one on the bottom, well you already know what one that is. its the broken 92-93 sc300 ecu.
its possibly the most available kind of sc300 ecu. I would not waste any time and just get a working 92-95 sc300 ecu as I said without trac if possible.
PM Aliga in the classifieds he may have one sitting around. also check in the classifieds for any auto 92-94 or even 95 ecu should help you out.

ACCHRM

Thanks for the respond, I already bought a new one, just waiting for it to arrive. Havent really thought of looking up from what car is it, the seller that i got the car from just said it was from "his" previous manual SC3... WIll post update when the new ecu arrives, I hope it fixes everything.

Ali SC3

iTrader: (10)

well I knew what he told you did not make much sense because auto ecu's can be used on auto or manual car's, but a manual ecu will not work on an auto car. the engine might turn on but it literally has no way of controlling the trans, none, nada, wouldn't work whatseoever..

so then I just typed in "89661-30682" into google (the number on your top ecu there).
results
https://www.google.com/search?q=8966..._sm=0&ie=UTF-8

and then from the results list I usually choose the lexus link because it has the most accurate numbers
http://www.lexuspartsnow.com/parts/l...661-30682.html

and it says GS300 1994-1996 6 Cyl 3.0L
and all gs300's are automatic.

let is know how the SC300 ecu works out when you get it, also do the same part number check on ecu's you buy so you know they are right, don't rely on someone else to type it into google for you or you will get wrong answers and get nowhere. good luck!