Check Engine after JWT ECU mod

Hi there,I just installed a JWT modified ECU on my Max. But after driving it about 300 miles a check engine code came up:

0504 Automatic Transmision control unit or circuit fault

Does this mean that my Transmission Computer is damaged or is it just that it's not completely compatible with the mod made to the ECU??

what transmission is your car ? if you have a manual and the ecu you had upgraded is an ecu out of an auto it will throw that code. not sure on anything else. when i was searching for my manual ecu, these folks sent me the wrong one. it was for an auto, i knew it would work in my manual and i put it in and drove around a week, and then sent it back. i got that code with it in though, the ecu is searching for a auto tranny or something.

now in your case im not sure..whats up ? a 96 manual ecu should have a sticker on it white/orange saying B6 and autos are B5

Mine is a 96 automatic Maxima and the JWT modified ECU comes from a 95 automatic Maxima.

95's are obd 1 and 96's are obd-2. that shouldn't effect your tranny though. it's funny, my new car threw out that code too when i first got it and I don't even have an auto. they just reset the ecu and it never happened again. does the car run ok?

yeah it runs fine, I havent checked it to see If it gives the same code again, but the transmission is running great as always! I guess I shuouldnt worry then

i was really pissed when it happened to me cuz pulling a code for an auto tranny on a 6 speed gave me the impression that this car was tinkered with, but it's still all good and it hasn't happened again in the 6 months i had the car.