OBD readiness - oxygen sensors incomplete

Jhill

Like posters said before your tuner likely turned it off because of the cats. I’m a little confused by this though as the rear 02 ran and passed and those are the ones that would/should likely fail without cats. The rear o2’s with a good cat should have slow low amplitude switching voltage and hover around 1/2 a volt, without the cats it should be switching rapidly between about .1-.9 volts. You can make sure the fronts and enabled and then runs the extend j bend bungs for the rear o2’s if you don’t have to pass a visual. This will give you full functionality of the fronts and dilute the exhaust that the rear 02’s see.

370z_stillen

Thanks for your reply. The rear o2 sensors give a 'good reading' because the front are disabled, so the rears are the first to receive the readings. If the tuner enables the front as well, the reading at the front will be the same as the rear and then the rear o2 will likely fail. I am thinking about adding the mini cats of go back to HFCs instead of empty cats, some more research to do first!