I have a 1993 Honda accord. the tranny doesn't change gears and the D4 light stays on even though you change gears. it turns off when you accelerate it quick from a complete stop. their is no check engine light. I changed the solenoids and it fixed my problem for approx two days. i was told it was the tcu but I want to see what others say?

 

TCU. i have a 91 that has same problem. I had asI ked the person i bought it from and she had told me she had a compter changed and it was fine. If it sometimes goes into gear from park and sometimes it dont, then the TCU would be my guess. Hopefully i will be buying one from the scrapyard this weekend. if i do i can let you know if that fixed my tansmission problem

 

If the D4 light is on all the time there is a hard fault, and a code stored in the TCU. To access TCU codes you will need to jumper the blue two wire diagnostic connector that is located above the passenger kick panel. This is the same connector used to check for CEL codes. Turn ignition to II(ON) and watch the D4 light blink, record codes, post them here.

 

i feel your pain same thing happened to my car then i changed the main relay and the d4 flashing problem i had was fixed if you can't find it got to you tube and type in eric the car guy then you car year and make then main relay problem should help