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obligation under federal law to implement stricter vehi-
cle emission standards to reduce air pollution from ve-
hicles. A dynamometer is a treadmill or roller-like test-
ing device that allows your vehicle’s wheels to turn
while the vehicle remains in one place. Depending on
the severity of a state’s air pollution problems, the
states must adopt either a “basic” or “enhanced” vehi-
cle emission inspection test. Normally, a portion of the
basic emission test consists of an emission inspector
inserting an analyzer probe into the exhaust pipe of an
idling vehicle for a short period of time. States with
more severe air pollution problems are required to
adopt an enhanced vehicle emission test. This test
simulates actual driving conditions on a dynamometer
and permits more accurate measurement of tailpipe
emitted pollution than the basic emission test.
The U.S. Environmental Pr otection Agency (EPA) and
states using two-wheel dyna mometers in their emis-
sion testing programs have EXEMPTED SUBARU
AWD vehicles from the portion of the testing program
that involves a two-wheel dynamometer.
There are some states that use four-wheel dynamom-
eters in their testing pr ograms. When properly used,
that equipment will not damage an AWD SUBARU ve-
hicle.
Under no circumstances should the rear wheels be jacked off the ground, nor should the driveshaft be dis-
connected for state emission testing. The EPA has issued regulation
s for inspecting the On-
Board Diagnostic (OBD) system as part of the state
emissions inspection. The OBD system is designed to
detect engine and transmission problems that might
cause vehicle emissions to exceed allowable limits.
These inspections apply to all 1996 model year andnewer passenger cars and li ght trucks. Over 30 states
plus the District of Columbia have implemented the
OBD system inspection. y The inspection of the OBD system consists of a vi-
sual operational check of the “CHECK ENGINE”
warning light/malfunction indicator lamp (MIL) and an examination of the OBD system with an electronic
scan tool while the engine is running. y A vehicle passes the OB D system inspection if
proper the “CHECK ENGINE” warning light/MIL illu-
mination is observed, there is no stored diagnostic
trouble codes, and the OBD system readiness moni-tors are complete. y A vehicle fails the OBD inspection if the “CHECK
ENGINE” warning light/MIL is not properly operating
or there is one or more di agnostic trouble codes stored
in vehicle’s computer with the “CHECK ENGINE”
warning light/MIL illuminated.
