I had the exact same problem two years ago and a friend helped me with a letter to get me through DMV this year I'd actually like to figure out what the hell's going on. On the DMV letter in the Readiness monitor status it says O2 sensor and Catalyst not ready. I've been to my friends repair shop and check for codes and none come up. It makes no sense to me whatsoever I'm wondering if anybody has any thoughts. Thank you

 

all the monitors have to run and pass to pass the inspection. the monitors have multiple states
-failed...the test has run and failed and a dtc is set
-completed...the test has run and passed
-not ready...conditions to run the test have not occurred...codes are not set as it hasn't failed. it hasn't passed either. You must find out what the required conditions are and do them during the test drive for the monitor to run. Each monitor has its own requirements before it runs a test.


-the 02 monitor must run and pass before the catalyst monitor will run. so figure why the o2 monitor isn't running first.

 

So,before this last trip to shop,when was the last time power was interrupted or a plug in to the aldl?