o2 sensors

[impulsesv6]

i have a "check powertrain" light/warning coming on,
took the car to holden and they said the o2 sensors are playing up,
but wouldnt tell me which ones.
they say that cos i have exhaust work they arent covered under warranty.

i then took the car to my tuning ppl and they said the right bank sensors are playing up,

one reason could be cos the rear sensors have been placed too far back from the motor

just wondering if there is any way to tell which one is playing up (front or rear)
multimeter or somthing?

if both o2 sensors test good then the rears are most probably too far back

 

[Not_An_Abba_Fan]

There is a test you can do measuring the voltage from the sensor, it has to be done when the car is warm and revving at about 2500 rpm so the sensors are hot and at operating temperature. A normally operating sensor will fluctuate rapidly between 0 and 1v, if it remains up around 0.8v then it is running rich, if it stays low, then it is running lean. To test to see if it is working properly, clamp off the fuel return line slightly raising fuel pressure and the voltage should go up. If you can't get a reading then maybe it is too far down the system and not getting hot enough.