[doug maire]

I finally got to the bottom of the problem. Apparently there are 2 tests that are performed on an OBD2 system. The first is a readiness monitor test and the second is the ODB sensor error test. The readiness test is to verify that all the sensors have run their system checks and have reported back to the OBD computer. The second test is to see if those sensors have recorded any errors from those sensors. The problem with the early Subaru OBD2 systems is that some were designed to cut off power to the OBD computer every time the ignition is turned off (which resets the readiness every time) or they have an extremely long drive cycle (as much as 1,000 mi), which prevents the readiness monitors from setting under a normal drive cycle. Unfortunately Arizona Emission Test requires that the ignition be shut off before conducting the readiness testing. As a result the OBD reports that the system is not ready and the vehicle fails. After 3 failed attempts I discovered that the AZ Dept of Transportation has a list of vehicles that have these design errors in their OBD systems and they exempt those vehicles from the readiness test. In Lieu of the readiness test DMV conducts a check engine light test to assure that the check engine light is functioning correctly.