i have a code P0170....FUEL TRIM MALFUNCTION (BANK 1) can anyone explain this code.....need to pass the smog check

 

The o2 sensors constantly switch the fuel mixture from rich to lean above 2400 rpm to achieve 19.7 to 1 air/fuel ratio. If an o2 sensor is lazy and slow to switch it can kick this code as well as a vacuum leak/dirty injector etc.

 

thanks Hixx........ i will check all the lines and change my O2 sensors......van is 11 years old I guess its about time to replace the O2 sensors.....can I use a universal type sensors ?

 

Yes the aftermarket sensors are fine.