a couple of weeks ago, i had to change the transmission in my 98 honda civic because the engine light came on and the engine codes read P0700 and P0730 which are automatic transmission control system malfunction and incorrect gear ratios. My transmission was basically slipping so i bought a used one and swapped them. A few days ago, the check engine light came back on and the code is the same P0700 automatic transmission control system malfunction but the other one is gone. The D4 light on the gauge cluster flashes sometimes too. I was wondering if anyone would know anything more about the control system and what my problem might be.
thanks!

 

Isn't there a seperate ECU that controls the transmission in an auto?

 

ya there is a seperate ECU for auto trannies my 1990 accord had one so i woul assume that other obd1-obd2 honas also have them. it should be located near the steering column near the fuse panel i think