Malfunction; Indicator Lamp - GMC 2010 Acadia Owner's Manual

Malfunction

Indicator Lamp

A computer system called OBD II
(On-Board Diagnostics-Second
Generation) monitors operation of
the fuel, ignition, and emission
control systems. It ensures that
emissions are at acceptable levels
for the life of the vehicle, helping to
produce a cleaner environment.
This light comes on when the
ignition is on, but the engine is not
running, as a check to show it is
working. If it does not, have the
vehicle serviced by your dealer/
retailer.
If the check engine light comes on
and stays on, while the engine is
running, this indicates that there is
an OBD II problem and service is
required.
Malfunctions often are indicated by
the system before any problem is
apparent. Being aware of the light
can prevent more serious damage
to the vehicle. This system assists
the service technician in correctly
diagnosing any malfunction.
If the vehicle is
continually driven with this light
on, after a while, the emission
controls might not work as well,
the vehicle's fuel economy might
not be as good, and the engine
might not run as smoothly. This
could lead to costly repairs that
might not be covered by the
vehicle warranty.
Instruments and Controls
Modifications made to the
engine, transmission, exhaust,
intake, or fuel system of the
vehicle or the replacement of
the original tires with other
than those of the same Tire
Performance Criteria (TPC) can
affect the vehicle's emission
controls and can cause this
light to come on. Modifications
to these systems could lead to
costly repairs not covered by
the vehicle warranty. This could
also result in a failure to
pass a required Emission
Inspection/Maintenance test.
See
This light comes on during a
malfunction in one of two ways:
Light Flashing: A misfire condition
has been detected. A misfire
increases vehicle emissions and
could damage the emission control
system on the vehicle. Diagnosis
and service might be required.
5-17
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