Do you have an OBDII reader? The CA (like NV) is a OBDII check. First, if you have a check engine light (active code) it will not pass, period. Second, they look for "system readiness". I had been told that CA was going to be an "all ready" state in the next few years, but that right now you should be allowed ONE system not ready [except evap still has to be ready] and still pass. So if you failed either (1) you have another system not ready indicator or (2) the test station didn't do it right. My cat converter is also not ready, and passes in NV.
Also, get your self an OBDII reader. I got a bluetooth one for about $20 from Amazon.com and use a phone app to get the data. At least in NV, you are allowed one free re-test, after which time you have to pay, so get the reader and twiddle until you get all ready (if that is what they require).