s shifter light

I have a 91 honda accord just lately the s light on the shifter has been coming on making the car go down to 45 and won't go any faster. I know the s on the shifter is for sport shifting I think and should not come on unless you push the button in. I have no codes showing up on the car but when the s light comes on it does this sometimes it stays on or goes off and on. When the car is sitting sometimes while idling the shifter clicks 2 times and then the s light stays on. I can't figure out what it is if it shows no engine codes but the s light I am not sure why when it comes on by itself makes the car do this.

Are you connecting the test jumper to get the error codes? Turn the car off, go to the right hand side of the passenger dash. Below the glove box, near the kicker panel (to the right) should be a blue connector with two leads. Connect the leads, and switch the car to on (position II, I believe) - no need to start the car. The S light should blink. The engine light might blink, too. count the number of blinks and that's your error code. It sounds like one of the transmission soleonids is refusing to engage, although it could be some other problems. The error code will tell you.