GMC 2010 T-Series, Owner'S Manual

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Malfunction Indicator Lamp
Check Engine Light
A computer system called OBD II (On-Board
Diagnostics-Second Generation) monitors operation
of the fuel, ignition, and emission control systems.
It makes sure that emissions are at acceptable levels
for the life of the vehicle, helping to produce a cleaner
environment.
If this light comes on
while you are driving,
two things can happen.
First, you will not notice any difference in engine
performance, but the tail pipe emissions might increase.
Second, the engine might not run properly or could stall
without warning. If either of these things happen, see
your dealer/retailer for service.
This light should come on when the ignition is on, but
the engine is not running, as a check to show it is
working. If it does not come on at all, have it repaired.
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 5 ‑ 3 .
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.
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