hi,
1998 accord ex 4cyl. ulev v-tec. had a transmission rebuild in october. recently threw a po740 code. took it to warranty shop. replaced a 80425 honda sensor. same code. claimed data analyzer read different rpm at engine and transmission. replaced ecm with used one, flashed by honda dealership. now throws a po135 code and po740 code. i swithched ecm back to original. no po135 code but po740 is back after road test at 60mph. warranty shop claimed rpms were equal after ecm was changed but still had 740 code. would used ecm have a bad code already in it?(po135) thanks

 

p0135 is an oxygen sensor code -- totally unrelated.

p0740 indicates the torque convertor lockup clutch is slipping. IMO, your rebuilt transmission is failing and the shop is trying to give you the run-around.

 

thanks for the response. changed ecm back to original. no 135 code. cleared all codes with scan tool. test drove in D3 at highway speed. no code appeared (CEL) but of course higher rpm. need to get this smogged. will running in D3 be all right till computer relearns and I can get through smog?