got problems with the ecu on a 2003 focus ...
hi, i have an 03 focus LX 2.3L and recently i have replaced the engine on the car. i went and try to pass smog with it but it seems that the computer from the smog place it cannot connect to the ECU. i even tried some other diagnostic computers on the car still nothing. i have checked all the fuses and the relays and all of them are ok, the car runs great and i made sure all the plugs where plugged back in after i installed the new engine. my question is if anybody knows what might cause this problem to be impossible to connect to the ecu? thank you and i'm waitting for your oppinions.