0s2 not ready wont pass inspection
 

So first check engine light was on 2011 equinox 4 cylinder. The mechanic replaced the catalytic converter to include the upline sensor and downline sensor cant remember the exact names but that how he explained it to me. Left the mechanic and CEL came back on. Again he said the only other thing it can be is ECM computer that fits over battery from what I can see another $600 dollars okay well know the CEL isnt coming on but the 0s2 will stay at not ready which means it will not pass inspection. I read on You tube maybe a bad battery i went and replaced that because it was saying it could use a charge and sense the battery is already 2 years old i figured I's replace it. Now I've driven 200 miles and still says not ready. Wondering if anyone else had issues like these when trying to get inspection and it says Not ready only in the 0s2. Purchased new gas cap too Please any advise you have as to try next much appreciated.

Are any codes present? The CEL doesn’t have to be on in order for codes to be stored, so double check if you’re not sure - it may require an advanced scan tool or phone app w/ OBD2 dongle to read them.

Assuming all related circuits and components are in tact and functional, there’s no reason for the O2 sensor to remain in a not ready state after that many miles. The first thing that comes to mind is the heater circuit isn’t fully functional.

im having a similar issue with my 2012 equinox after replacing the battery i went to inspect and was told that because i recently replaced the battery i need to drive it around for a couple weeks so it can reset. do you ever find a solution to the problem?

Thank you, now I've replaced the ECM and both sensors upper and downstream. The shop said they changed the plugs know I'm not sure because I keep getting the code 2271 and also 1st bank error. They also cleaned the muf with some kind of cleaner he said it was something special ? not sure what it was called because he didn't give me a receipt.

I didn't find a solution to my situation however, on your question I did have to drive around several times to get all the items required to be in the ready state. In the past I did take it in a couple times to soon and had to come back but usually you only have about 7 days otherwise you have to pay again. If you have a scanner check it before you go and make sure all items are ready.