User guide

AutoEnginuity ScanTool User Guide 31
OnBoard Test Results
The OnBoard Test Results window is used to display the
results from the onboard diagnostic inspection/maintenance (IM)
monitors. The engine computer monitors the status of up to 11
emission-control related systems by performing either continuous
or periodic function tests. The first three testing categories—mis-
fire, fuel trim, and comprehensive components—are continuously
running during the drive cycle. The remaining eight run only once
per drive cycle and only after a certain set of conditions are met.
Typically, vehicles will have at least five of the eight remaining
monitors (catalyst, evaporative system, oxygen sensor, heated oxy-
gen sensor, and exhaust gas recirculation, or EGR, system) while
the remaining three (air conditioning, secondary air, and heated cat-
alyst) are not necessarily applicable to all vehicles.
Most states now use the IM monitors to determine whether a
vehicle passes their emissions requirements. Which IM monitors
are used for testing is not standardized. If your vehicle doesn’t have
the necessary monitors in the "Completed" state, a tailpipe gas anal-
ysis might be used instead of allowing your vehicle to fail. Contact
your local emissions facility to determine which IM monitors are
used for testing and what the emissions requirements are for your