cec 743

crashpaq · Post by **crashpaq** » Sat Oct 13, 2007 11:24 am

I have read the description, but do not understand "P0743 Torque Converter Clutch Solenoid/ Trans Relay Circuits An open or shorted condition detected in the torque converter clutch (part throttle unlock) solenoid control circuit. Shift solenoid C electrical fault - Aisin transmission " please help

thanks
Nick

aperson · Post by **aperson** » Sat Oct 13, 2007 12:21 pm

Does your car have an ATX or MTX? If you did an MTX swap recently then you need to re connect the torque converter lockup solenoid to get rid of the code. If you have an ATX then you need to replace the solenoid.

crashpaq · Post by **crashpaq** » Sat Oct 13, 2007 7:42 pm

so i have an atx, and what exactly is a torque converter lockup solenoid. The car is still running fine.

aperson · Post by **aperson** » Sun Oct 14, 2007 12:45 am

Look up "how stuff works torque converter" I don't really know what's wrong if it still runs fine.

SGT BRAD · Post by **SGT BRAD** » Mon Oct 15, 2007 6:01 pm

iirc the lock-up saves wear and tear on the tranny by locking the tranny to the motor in a 1:1 at highway cruising speeds. for whatever reason your's ain't doing it. imagine the decrease in wear by the valve body not doing the work while motoring along at 70mph.

BlackRoseRacing · Post by **BlackRoseRacing** » Mon Oct 15, 2007 6:52 pm

is your 3 prong harness plugged into the front of the trani near the dipstick tube?
The wiring is also known to corrode and make no contact....

Post by **occasional demons** » Wed Oct 17, 2007 3:25 pm

SGT BRAD wrote:iirc the lock-up saves wear and tear on the tranny by locking the tranny to the motor in a 1:1 at highway cruising speeds. for whatever reason your's ain't doing it. imagine the decrease in wear by the valve body not doing the work while motoring along at 70mph.

It won't save any wear on the valve body, but it will on the engine and as far as heat the trans. More than those issues it's for fuel economy. I would agree with BBR- check connections, and moniter fluid level the hotter the fluid the higher it will rise. City driving should be hotter than cruising @60mph because the converter is unlocked more in city as where criusig @ 60 it should be locked keeping temps down. If you listen to the motor (assuming you don't have a tach) you should be able to tell if its working. count the shifts for each gear don't know if 3 or 4 speed when it hits top gear at light throttle you should hear if not feel another subtle "shift" (If the clutch itself is good) usually about a 200 rpm drop give or take 50 rpm