But do you have a stage 2 tune that disables the CEL? Or does your downpipe just perform well enough to prevent the light? I don't think it's possible to disable the secondary O2 sensor without at least one readiness failure. In my state we are able to pass emissions with one readiness failure so I was curious which monitors would be disabled on this platform when disabling the secondary O2 sensor.Recently had my inspection done. All my readiness monitors show ready and I am running a CTS turboback exhaust with a cat and no spacer. The cat is in the midpipe and not in between the two o2 sensors so its literally not factoring into the monitors at all, just there for show and to indeed filter the exhaust.
I still have codes for o2 sensor lean, and efficiency below threshhold, but they don't cause the CEL to illuminate and the car passed just fine.
-Matt