2.4 OBD II Readiness Monitors – (or IM Monitor)
An important part of a vehicle’s OBD II system is the Readiness
Monitors, which are indicators used to find out if all of the
emissions components have been evaluated by the OBD II system.
They are running periodic tests on specific systems and components
to ensure that they are performing within allowable limits.
Not all monitors are supported by all vehicles and the exact number
of monitors in any vehicle depends on the motor vehicle
manufacturer’s emissions control strategy.
Continuous Monitors
-- Some of the vehicle components or
systems are continuously tested by the vehicle’s OBD II system,
while others are tested only under specific vehicle operating
conditions. The continuously monitored components listed below
are always ready:
1) Misfire
2) Fuel System
3) Comprehensive Components (CCM)
Once the vehicle is running, the OBD II system is continuously
checking the above components, monitoring key engine sensors,
watching for engine misfire, and monitoring fuel demands.
Non-Continuous Monitors
-- Unlike the continuous monitors,
many emissions and engine system components require the vehicle
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