Chevrolet Repair: 2003 S10 OBD Readiness, tailpipe emissions, emissions standards

Question
2003 Chevy S10 LS 4WD The "Service Engine Soon" light came on and the garage replaced the O2 sensor. Now the OBD reads that it is not ready for emissions tests (required for PA inspection). I have gone back 3 times for the emsissions inspection after driving the truck and still get the not ready code. I just found a reply about the GM drive cycle on this site. Do I need to follow this exactly before the OBD will read ready for the emissions inspection?

Answer
Hiya,

  This is an interesting topic because my provinces emissions laws and standards for testing are different than yours but I might be able to help you.
  Ontario has implemented emissions standards fairly recently.  Depending on the population of the city we have testing requirements in different stages and unfortunately the rules are changing on the fly.  When it was first fired up (1999) a vehicle's 'green' status was good for one year.  If the vehicle did not change hands it was good for two years to the date of the registered person's birthday.  So when you would renew your plate charges you would get a notice roughly 90 days in advance to get it tested.
  Initially all cars, trucks and buses were tested for tailpipe emissions and check engine light.  If the check engine light was on the test could not be initiated.  This rule was bypassed early on due to some check engine light issues not being related to tailpipe emissions at idle or load test.  At this point all that is tested in Ontario is the idle gases and the load gases.
 A system monitor is complete when either all of the DTCs comprising the monitor have run and passed or any on of the DTC have set the light.  You need to make sure there is NO trouble codes and then do at least 3 complete drive cycles. Do not disconnect the battery between cycles and do not attempt code clearing.  Scan trans and BCM for codes as well.

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