GMC 2011 Sierra - Manual (Page 174)

Black plate (26,1) GMC Sierra Owner Manual - 2011
5-26 Instruments and Controls
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 vehicle off, wait at
least 10 seconds, and restart the
engine. If the light is still flashing,
follow the previous steps and see
your dealer 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.
The following may correct an
emissions system malfunction:
. Make sure the fuel cap is
fully installed. See Filling
the Tank on page 9‑88.
The diagnostic system can
determine if the fuel cap has
been left off or improperly
installed. A loose or missing fuel
cap allows fuel to evaporate into
the atmosphere. A few driving
trips with the cap properly
installed should turn the light off.
. Make sure the electrical system
is not wet. The system could
be wet if the vehicle was driven
through a deep puddle of water.
The condition is usually
corrected when the electrical
system dries out. A few driving
trips should turn the light off.
. Make sure to fuel the vehicle
with quality fuel. Poor fuel quality
causes the engine not to run as
efficiently as designed and can
cause: stalling after start-up,
stalling when the vehicle is
changed into gear, misfiring,
hesitation on acceleration,
or stumbling on acceleration.
These conditions might go away
once the engine is warmed up.
If one or more of these
conditions occurs, change the
fuel brand used. It will require at
least one full tank of the proper
fuel to turn the light off.
See Recommended Fuel on
page 9‑84.
If none of the above have made
the light turn off, your dealer can
check the vehicle. The dealer
has the proper test equipment
and diagnostic tools to fix any
mechanical or electrical problems
that might have developed.