Equus 3160 - ABS/SRS + OBD2 Scan Tool - Manual (Page 44)

Using the Scan Tool
I/M READINESS TESTING
42 OBD2
The program requires that a vehicle be taken periodically to an
Emissions Station for an "Emissions Test" or "Smog Check,” where the
emissions-related components and systems are inspected and tested
for proper operation. Emissions Tests are generally performed once a
year, or once every two years.
On OBD2 systems, the I/M program is enhanced by requiring vehicles
to meet stricter test standards. One of the tests instituted by the Federal
Government is called I/M 240. On I/M 240, the vehicle under test is
driven under different speeds and load conditions on a dynamometer for
240 seconds, while the vehicle's emissions are measured.
Emissions tests vary depending on the geographic or regional
area in which the vehicle is registered. If the vehicle is
registered in a highly urbanized area, the I/M 240 is probably
the type of test required. If the vehicle is registered in a rural
area, the stricter “dynamometer type” test may not be required.
I/M Readiness Monitors
I/M Readiness shows whether the various emissions-related systems on
the vehicle are operating properly and are ready for Inspection and
Maintenance testing.
State and Federal Governments enacted Regulations, Procedures and
Emission Standards to ensure that all emissions-related components
and systems are continuously or periodically monitored, tested and
diagnosed whenever the vehicle is in operation. It also requires vehicle
manufacturers to automatically detect and report any problems or faults
that may increase the vehicle's emissions to an unacceptable level.
The vehicle's emissions control system consists of several components
or sub-systems (Oxygen Sensor, Catalytic Converter, EGR, Fuel
System, etc.) that aid in reducing vehicle emissions.
To have an efficient Vehicle Emission Control System, all the emissions-
related components and systems must work correctly whenever the
vehicle is in operation.
To comply with State and Federal Government regulations, vehicle
manufacturers designed a series of special computer programs called
"Monitors" that are programmed into the vehicle's computer. Each of
these Monitors is specifically designed to run tests and diagnostics on a
specific emissions-related component or system (Oxygen Sensor,
Catalytic Converter, EGR Valve, Fuel System, etc.) to ensure their
proper operation. Currently, there are a maximum of eleven Monitors
available for use.
Each Monitor has a specific function to test and diagnose only
its designated emissions-related component or system. The
names of the Monitors (Oxygen Sensor Monitor, Catalyst
Monitor, EGR Monitor, Misfire Monitor, etc.) describe which
component or system each Monitor is designed to test and
diagnose.