i have a 93 accordand the d4 light was blinking all the time. i have no problem with it starting. i got another tcu from a salvage yard and installed it. with the old tcu it seemed to only have 2nd and 3rd gear and with the other one it seems to shift from 1st to 3rd. i jumpered the connector and the d4 light flashes 7 times. the d4 light doesn't come on till i try to go forward. i have drained and refilled tranny. any help would be great.

 

7 flashes would mean a code 7 (if it is 7 even flashes). you need to look up in a service manual what 7 flashes mean. I don't know if the 93 was OBD I or not, but autozone should be able to help you. if not, they do sell a haynes/chilton manual for $15; if you don't have any, get one anyways, it's a great investment...

quick google search says that a code 7 is shift control solenoid, don't know if thats right though...

 

this is my 1st honda and not sure what you mean by OBD.

 

OBD is just how the code is outputted. there is OBDI and OBDII. OBDII can use a code puller, OBDI requires you to look through a sight window and count the flashing or jumper a cable and count the flashes of the CEL.

one of the suggestions I read is to unplug the alt fuse or just the neg battery terminal for 30sec-1min. drive around and see if that cures your problem until you come to a stop. if so, then it says it is your TCU, but since you had 2 "bad" TCU's it makes me think its a different sensor.

 

d4 is flashing due to poor quality chips in tcu.

solution is to disconnect battery cable for 5min. this should fix for a while if flashing reoccurs repeat process with battery cable. you will have to reset time and radio.
cost of repair 0$dollars and .0$cents

my 94 accord d4 flashes about anywhere from 2months or as little as two week intervals disconnect batt. fixes everytime.