Model GS300 2005-2011
Got 3 lights on my dashboard. I have replaced the rear oxygen sensors.
The code is showing that catalytic converter on bank 2 needs to be replaced, and one of my friends in a garage told me so as well.
However, he didn't tell me what caused the problem. As people say, I need to find out the real problem before I replace the CAT.
I took some real-time readings from my OBD reader, and found sensors on bank 1 perfectly normal (of course), and sensors on bank 2 showing "not used"
As far as I knew, the O2s will not be used in open loop. However, the fuel system status is closed loop, which means O2 sensors are being used. And also sensors on bank 1 are working well.
Then on wiki, I found this: (if B==$FF, sensor is not used in trim calculation).
This is not for the O2 voltage, but the short term fuel trim calculation formula.
The $FF stands for the maximum possible value. So does this mean all 2 oxygen sensors are working at full capacity? What does this mean?
Could anybody help me find the true cause of the problem please?
Thanks.
Hi Steve, Thanks for your reply. Cannot believe I forgot to mention the model. It is actually GS300, not IS. The sensors on bank 1 are okay because: sensor 1's voltage is around 0.5 and sensor 2's is around 0.1, so I thought they were good. I didn't understand the fuel trim figures, but I will do some research and try to read them again. My car had a main service in Jan 2016, but I am not sure whether they check ignitions or not. I presume they check and replace filters. Have you got some more ideas please? Thank you.