GMC 1999 Envoy Owner's Manual page 134

Security Warning Light
If the light flashes, the Passlock
tamper mode. If the vehicle fails to start, see "Passlock"
in the Index.
If the light comes on continuously while driving and
stays on, there may be a problem with the Passlock
system. Your vehicle will not be protected by Passlock,
and you should see your dealer.
This light should also flash as you open the door (if your
ignition is off). This is a reminder to activate the
-
theft deterrent system. See "Content Theft
the Index for more information.
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This light will come on
briefly when you turn the
key toward START. The
light will stay on until the
engine starts.
R
system has entered a
-
Deterrent" in
Service Four-Wheel-Drive Warning Light
Your vehicle is equipped with the Automatic
- -
Four Wheel Drive Transfer Case. It has a computer
-
which controls the four wheel
The SERVICE 4WD light comes on to indicate that
there may be a problem with the Automatic Four
Drive system and service is required. Malfunctions can
be indicated by the system before any problem is
apparent, which may prevent serious damage to the
vehicle. This system is also designed to assist your
service technician in correctly diagnosing a malfunction.
-
drive system.
This light should come on
briefly when you turn on the
ignition, as a check to show
you it is working.
-
Wheel
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