OBDII code reader still lights up yellow..?

[NaturallySmashed]

okay so I recently had a code for a thermostat and smog pump.. replaced both of those.. cleared the codes.. the ses light hasn't come back on.. this was about 4-5 days ago.. so i plugged back in the code reader .. it didnt pull any codes.. but the emissions "pass light" didn't come on.. the yellow light came on

"yellow LED.. indicates there is a possible problem. A "pending" DTC is present and/or some of the vehicles emmission monitors have not run their diagnostic testing."

so i cleared the obd again... did a 400 mile trip within the past 3 days.. and i plug in the code reader only to get the same yellow light.. no codes.. just the yellow light.. what's the deal with this? anybody ever have this problem? i'd think 400 miles was enough to get the light to green!!

[Scimmia]

A single trip on the highway may not be enough, it's just just about miles, the tests have to see specific conditions to complete.

[TDCRacing]

or some of the vehicles emmission monitors have not run their diagnostic testing."

X2....

[NaturallySmashed]

http://www.grandprixforums.net/dtc.php

these tests? and they have to be done in that order? is there a way to put it into diagnostics mode?