I did some data logging the other day with Autotap. I noticed that my O2 Sensor Bank 1 Sensor 2 (MV) is always showing 0. Which sensor is this? What could this cause in regards to my tune? Any help with this would help. Also I do not have any SES lights.

Rich

 

that is the post cat sensor. It is common to see what you are seeing. I'd bet that if you romped on it a few times you may come up a bit and back to 0. Your tuner can basically kill those readings with a chip.

They are there basically for a stock setup to tell the computer whether you cats are working or not.

Sensor 1 is what you'd wanna worry about.

 

From the reading I have done it should always read 0 or very close to it. That tells the computer that the cat’s are doing their job correctly. If it fluctuated like the 02 sensor before the cat it would indicate the cat is bad and not doing its job and thus setting a code.

That is the main reason when someone guts their cats they have to have the rear 02 sensors shut off with a tune.