My car did not pass its emission test because it wasn't "ready." What is it supposed to be ready for?
Newer-than-1996 vehicles are equipped with an on-board diagnostic (OBD) system that is constantly monitoring, testing and looking for faults. The powertrain control module (PCM) is the brain of the OBD system, managing a multitude of items within the engine and emission systems. The terms "readiness" or "ready" refers to the status of the PCM.
After a trip to the repair shop or with the code reader you bought at a flea market, resetting the PCM causes the readiness monitors to change to an "incomplete" status. You will have to drive the vehicle through various conditions in order for the PCM to do its job and complete all of its tests. This is called a drive cycle and is a combination of city, highway driving and idling. Many cars can achieve readiness within one drive cycle but, as we all know, it can never be that easy. Two or three drive cycles are occasionally needed if you can't satisfy the test requirements within a single drive. Unfortunately, when you take your vehicle in for an emission test and it is not "ready," it is the same thing as a fail.
Haven't reset your PCM recently and your car is still not "ready"? Perhaps a software update is needed or a "pending" engine light is about to appear.
Lou Trottier is owner-operator of All About Imports in Mississauga. Have a question about maintenance and repair? E-mail globedrive@globeandmail.com, placing "Lou's Garage" in the subject area.
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