Operation Manual

5
5
connector. If the DLC cannot be found, refer to the vehicle’s service manual for the
location.
2.4 OBD II Readiness Monitors
An important part of a vehicle’s OBD II system are 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 run periodic tests on specific systems and
components to ensure that they are performing within allowable limits.
Currently, there are eleven OBD II I/M (Inspection Maintenance) Readiness
Monitors defined by the U.S. Environmental Protection Agency (EPA). 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 -- The individual components are continuously tested by the
vehicle’s OBD II system, while others are tested only under specific vehicle
operating conditions. The continuously monitored individual components listed
below are always “OK” (ready). Once the vehicle is running, the OBD II system is
continuously checking the individual components, monitoring key engine sensors,
watching for engine misfire, and monitoring fuel demands. These continuous
monitors are:
1. Misfire monitoring - detects abnormal variations in the crankshaft velocity.
2. Fuel System - monitors air/fuel ratio to ensure maximum fuel efficiency.
3. Comprehensive Components (CCM) - monitors individual sensors and actuators.
Non-Continuous Monitors -- Unlike the continuous monitors, many emissions
and engine system components use multiple sensors to ensure the integrity of
each system listed below. These system monitors require the vehicle to be
operated under specific conditions (engine speed, coolant temperature, duration of
Figure 1-1: The DLC connector (left) can be found in the area of
the car interior seen at right (black arrow).
MS309 Manual_V1.01.fm Page 5 Wednesday, January 7, 2009 2:42 PM