BrownGuy

iTrader: (1)

Hey guys. A buddy of mine recently got his SC300 which came with an auto trans that had a shifting problem, The final gear doesn't engage(this is with Overdrive on). At first we thought it was the ecu so we switched it out with a known working one. Same thing happened. He got fed up just got a different working auto trans(torque converter included). Same thing happened. so now we are stumped. Are there any other sensors the control the shifting points of the auto transmission?

EDIT:
Assuming that since the engine temp gauge works, the engine temp sensor should be working.

Any suggestions?

YeA 2jZ

iTrader: (15)

shift engagment points are controled by ecu, engine temp sensor, vss (speed sensors), and lastly shift solenoid in the transmission so anyone of those things could be causing ur troubles

BrownGuy

iTrader: (1)

Thanks! We have checked ecu, temp sensor and the solenoid in the new transmission seemed fine. So we will check the speed sensor. If the speedometer works, can we assume the speed sensor works tho?

kez

iTrader: (4)

this happened to me too,but i bought a whole five speed swap for $600

ishootstuf

iTrader: (1)

What year is the SC and did you use the same year ECU? Have you tried pulling codes?

Easwooth

Im having the same problem there are 2 vehicle speed sensors on the tail of the trans, one for cluster one input to trans, i changed both which did not fix my problem, changed fluid with filter, adjusted kick down cable and tps nothing scaned car fault says it could be tcc, vss or ecu two more to go if anyone has same issue and can help please starting to get desperate and running out of money. thanx

BIGCTY

iTrader: (2)

Are you SURE that ECU is good? I had the same issue, and thanks a couple of the same cats that have posted in this thread (especially ishootstuf as he sold me an ECU) that cured my issue.

vangb2

iTrader: (2)

perhaps it's your O/D switch is bad.

sillyboi12

iTrader: (-2)

get a whole new shifter it will work ! happened me and i change out the shift gate!

timber1426

hey man generally if your not going into over drive its most likly due to a knock sensor problem. But will throw a code.

BrownGuy

iTrader: (1)

Ok, since classes are over for now we were back at it. We checked all suggested:

Speed sensor-ok
O/D switch-ok (checked with volt meter in every gear)
temp sensor-ok
auto trans solenoid-ok
and finally ecu-ok (no check engine light)

and still nothing.... frustration is starting to set in...

BIGCTY

iTrader: (2)

My ECU wouldnt shift into O/D either and I did NOT have a check engine light. So if that is/was the method of testing the ECU.....

Sounds like the shift gate is next on the menu.

Ali SC3

iTrader: (10)

you got 2 speed sensors, and no, the speedometer working is not an indication that your speed sensors are both operating properly... it just means that one of them is, the less important one. so go check your other sensor according to the manual. its one of the main sensors a transmission uses for up shifting. the 2-wire speed sensor.

https://www.clublexus.com/forums/lex...1-install.html

https://www.clublexus.com/forums/sc-...sors-help.html

bbyrum

my 93 sc400 will not auto shift down to low,but i can put into low take off shift to 2nd and drive and it drives fine till i stop and go again. any ideas thanks?

imDementeD

iTrader: (7)

tranny solenoid more then likely..having same issue..ur O/D off light should flash..you can pull the code by jumping te1 and e1 then count the flashes of the O/D off light..itll let you know which solenoid is bad..mine was the first but im replacing both.