91 Accord stuck in S Mode
 

I have a 1991 Honda Accord and it's stuck in S mode The "S" mode will come and stay on after the car is started. Occassionally it will go off and on again during drive, causing the car to shift erratically. When it's on the only gear I hve to use is 3rd. I use the diagnostic plug under the glove and retrieved the following codes from the "S" mode light blinks (s=short blink, L=long blink, P=pause): 1s, p, 3s, p, 5s, p, 7s, p, 9s, p, 1L4s, p...then it repeats itself. What do the codes mean? I've read other forums saying to try cleaning the shift solenoids. Where are they located? What else can I try before replacing the TCU, and even then would it help?

thanks