GMC 2010 Savana 1500 Cargo Owner's Manual page 178

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.
Notice: 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.
Notice: 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
Accessories and Modifications on page 6-3.
4-32
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.
To prevent more serious damage to the vehicle:
•
Reduce vehicle speed.
•
Avoid hard accelerations.
•
Avoid steep uphill grades.
•
If towing a trailer, reduce the amount of cargo being
hauled as soon as it is possible.
If the light continues to flash, when it is safe to do so,
stop the vehicle. Find a safe place to park the vehicle.
Turn the key off, wait at least 10 seconds, and restart
the engine. If the light is still flashing, follow the previous
steps and see your dealer/retailer for service as soon
as possible.
Light On Steady: An emission control system
malfunction has been detected on the vehicle.
Diagnosis and service might be required.