Hummer 2007 H3 Owner's Manual page 187

This light should come on, as a check to show
you it is working, when the ignition is on and
the engine is not running. If the light does
not come on, have it repaired. This light will also
come on during a malfunction in one of two ways:
•
Light Flashing — A misfire condition has been
detected. A misfire increases vehicle emissions
and may damage the emission control system
on your vehicle. Diagnosis and service may
be required.
•
Light On Steady — An emission control system
malfunction has been detected on your vehicle.
Diagnosis and service may be required.
If the Light is Flashing
The following may prevent more serious damage
to your vehicle:
•
Reducing vehicle speed
•
Avoiding hard accelerations
•
Avoiding steep uphill grades
•
If you are towing a trailer, reduce the amount of
cargo being hauled as soon as it is possible
If the light stops flashing and remains on steady,
see "If the Light Is On Steady" following.
If the light continues to flash, when it is safe to
do so, stop the vehicle. Find a safe place to park
your vehicle. Turn the key off, wait at least
10 seconds and restart the engine. If the light
remains on steady, see "If the Light Is On Steady"
following. If the light is still flashing, follow the
previous steps, and see your dealer for service
as soon as possible.
If the Light Is On Steady
You may be able to correct the emission system
malfunction by considering the following:
Did you recently put fuel into your vehicle?
If so, reinstall the fuel cap, making sure to fully
install the cap. See Filling the Tank on page 318.
The diagnostic system can determine if the fuel cap
has been left off or improperly installed. A loose
or missing fuel cap will allow fuel to evaporate into
the atmosphere. A few driving trips with the cap
properly installed should turn the light off.
Did you just drive through a deep puddle of water?
If so, your electrical system may be wet. The
condition will usually be corrected when the
electrical system dries out. A few driving trips
should turn the light off.
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