I have a 1990 Accord LX,it acts like the trans is stuck in 2nd or3rd,unless you down shift to 1st. "S" light is stuck on,speedo works,shift solenoids function,and the book leads me to believe it's the TCU.I would appreciate any input.

 

I tried to clear the computer like the book says and it still does the same thing immediately.

 

Key off. Short the service connector under the glove box with a piece of paper clip.
Turn the key on, and count the flashes of the D4 (or S) lamp on the dash.
Mine had 1, 2, 7, and 8, but was shifting fine. I'm not sure what it's problem was, and I need to clear the errors and see if they come back. My car sat for about 8 months before I got it. Battery was dead so it probably wasn't old saved codes.

 

I've done that,no flashes,the"S" light just stays lit.

 

I think it would be a better idea to try toget the TCU codes before replacing the TCU.

Check all fuses as well.

The normal operation is the 'S' light comes on for a couple seconds when the key is turned on and runs a self check then turns off.

IFthe 'S' light does not go off after the self check, itis probably a bad TCU.

 

See DIY link https://www.hondaaccordforum.com/90-...m_28395/tm.htm.


good luck

 

Do you have a remote starter or alarm system? I had the same problem with my car a while back and I noticed there was an old alarm system installed so I tore it out (being careful not to cut any important wires and my shifting problem was fixed. My TCU was also making a clicking noise before I took out the alarm system.

 

where can the TCU be found
thanks honda dude

 

hello,
my s light stays on and trans will not shift out of second
whats the TCU and the location do u know the cost
thanks rob

 

I've seen the tcu's on e-bay for as little as $80. on the 90-93's it's located to the left of the steering wheel behind the dash. You can see it if you look up from the floor. It's a metal box about 3 x 4 inches.