On 9/19/2015 10:54 PM, Ewald Böhm wrote:
On Sat, 19 Sep 2015 05:44:13 -0700, sms wrote:

Can't speak for all states, but in California one of the first steps in
an emissions test is for the codes to be read via the OBD-II port.

I know this intimately not to be true, in the truest sense of what you say.

While many stations will certainly do a courtesy OBD scan, since you can't
pass CA emissions with a given number of pending or set codes or unset
monitors (the numbers of each are depending on the year of the vehicle),
it is absolutely NOT a requirement to run the OBD scan.

Look it up. I did.

You said it yourself. You can't pass emissions with pending codes. They
have to run a scan to check this. That's why before they even stick the
exhaust gas analyzer into the tail pipe they read the codes. No point
proceeding with the test if there are unset codes, though if you're
paying for the test they will complete it to check for other failure
modes as well.

At least that's the procedure for the four vehicles I have had smogged
every two years for the past 20 or so years. Also the procedure at the
repair shop my relative operated until he sold it last month, and he
probably did 3000 or so smog checks per year.

I guess you could claim that it is not a requirement to run a scan, it's
just a requirement that you can't pass with pending codes and the only
way to check for pending codes is to do a scan. If there is another way
to check for pending codes other than doing a scan you would be correct,
but I don't think that there is.