I am having a problem with my secondary O2 sensor. I took it to a shop and the guy there hooked up the OBDII scanner he had to my car but it didn't pull a code but the check engine light came on. On the OBDII scanner the Secondary O2 sensor said it was on but the voltage was 0 even after ideling the car for a long time and even after I drove it. What would cause the O2 reading to be 0 even though it said the sensor was on. Also what is the voltage supposed to be for the Primary O2 sensor. Using the SnapOn OBDII scanner the voltage was fluctuating between 2.90-3.10. By the way I have a 98 Accord Coupe with a converted manual tranny.