Sup everyone, I just rebuilt a tranny for an 04 accord sedan v-6. I installed the tranny and it runs fine, but whenever it goes into OD the d4 light begins to blink, but the car runs fine, shifts perfect and everything. Hooked it up to a scanner and get no codes. I rechecked all the connection and all is well. I drove the car for about 30min stop and go and all is fine. What could it be? Car came to me not moving and tranny was shot? I've rebuilt tons of hondas and this is the first time I ever had this problem.

 

My only guess is to reset the ecu if you haven't already. Good luck