Hondata

just purchase s300 from a distributor in california. my problem is when you plug the ecu in and turn the key to the on position the check engine light remains on. i have sent it back and he says it works fine with his test cars. just recieved it back plug it in and it does the same thing. the only catch is my cousin also had his done the same time and with his plugged in the light goes out after a few seconds. what could be wrong with my p28?

If you can upload but not dataload then the problem is the ECU socketing. Did you swap the s300 board into your cousin's ECU, or swap the whole ECU over?

talked with the dealer today and we figured it out. i ended up swapping the s300 out from my cousin's into my ecu and vice versa. his worked fine in mine and to my surprise my worked fine in his. it left me to conclude that it must have been installed off a pin or so. thanks for the response.