ecu dont show code trouble

[maik21]

i have a 240sx mod 90 and my ecu dont show other code. only show me code 55. i disconect the air temp sensor and the ecu show me the code 55. i remove the aiv and the ecu always display the same code. whats wrong? my car have bad gas mileage and the o2 diagnose(diagnostic) show me that the o2 sensor is ok. whats wrong with ecu>?

[NISTECH]

you have to put the car in a state that will trigger the code before it will show in the system and the system should not be in diagnostic mode when you are trying to trip the code. If you go to fast and pass up the code reading step and come back around to it the second time the codes will be cleared. its a 5 mode system if you go through all 5 modes and return to the code reader it will clear the code once you pass mode 5.

[maik21]

oks, thanks =)