At approximately 265°F (130°C), the driver information
center will display a TRANSMISSION HOT message
and the transmission will enter a transmission protection
mode. When the transmission enters the protection
mode, you may notice a change in the transmission
shifting patterns. The transmission will return to normal
shifting patterns when the transmission uid temperature
falls below 260°F (127°C).
SeeDriver Information Center (DIC) on page 3-50for
further information.
If your vehicle has an Allison transmission, and the uid
reaches temperatures of approximately 275°F (135°C)
or greater, the driver information center will display
a TRANS HOT IDLE ENGINE warning message and
a chime will sound until the temperature falls below
265°F (129°C). Pull the vehicle off the roadway when
it is safe to do so. Set the parking brake, place the
transmission in PARK (P) and allow the engine to
idle until the transmission temperature falls below
265°F (129°C). If the transmission continues to operate
above 265°F (130°C), contact your nearest dealer or
the GM Roadside Assistance Center. SeeRoadside
Assistance Program on page 7-6.Notice:If you drive your vehicle with the
transmission temperature gage above normal
operating range, you can damage the transmission.
This could lead to costly repairs that would not
be covered by your warranty. Do not drive your
vehicle while the transmission temperature gage
reading is above normal. See your dealer for service.
The following situations can cause the transmission to
operate at higher temperatures:
Towing a trailer
Hot outside air temperatures
Vehicle overloading
Hauling a large or heavy load
Low transmission uid level
High transmission uid level
Restricted air ow to the radiator and the auxiliary
transmission oil cooler (if equipped).
A temporary solution to hotter transmission operating
temperatures may be to let the transmission cool down.
If the transmission is operated at higher temperatures
on a frequent basis, seeScheduled Maintenance
(Gasoline Engine) on page 6-4for the proper
transmission maintenance intervals.
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Malfunction Indicator Lamp
Check Engine Light
Your vehicle is equipped
with a computer which
monitors operation of the
fuel, ignition, and emission
control systems.
This system is called OBD II (On-Board
Diagnostics-Second Generation) and is intended to
assure that emissions are at acceptable levels for the
life of the vehicle, helping to produce a cleaner
environment. The check engine light comes on to
indicate that there is a problem and service is required.
Malfunctions often will be indicated by the system
before any problem is apparent. This may prevent more
serious damage to your vehicle. This system is also
designed to assist your service technician in correctly
diagnosing any malfunction.
Notice:If you keep driving your vehicle with this
light on, after awhile, your emission controls may not
work as well, your fuel economy may not be as good,
and your engine may not run as smoothly. This could
lead to costly repairs that may not be covered by
your warranty.Notice:Modi cations made to the engine,
transmission, exhaust, intake, or fuel system of
your vehicle or the replacement of the original tires
with other than those of the same Tire Performance
Criteria (TPC) can affect your vehicle’s emission
controls and may cause this light to come on.
Modi cations to these systems could lead to costly
repairs not covered by your warranty. This may
also result in a failure to pass a required Emission
Inspection/Maintenance test.
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 mis re condition has been
detected. A mis re 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.
3-44
Highbeam On Light
This light will come on
when the high-beam
headlamps are in use.
SeeHeadlamp High/Low-Beam Changer on page 3-8.
Four-Wheel-Drive Light
The four-wheel-drive
indicator will light up
when you shift a manual
transfer case into
four-wheel drive and
the front axle engages.
Some delay between shifting and the indicator’s lighting
is normal.
SeeFour-Wheel Drive on page 2-37for more
information.
Tow/Haul Mode Light
This light is displayed
when the Tow/Haul mode
has been activated.
For more information, seeTow/Haul Mode on page 2-30.
Overdrive Disable
(Allison Transmission
®Only)
This light will illuminate
when the overdrive
disable feature is activated.
The overdrive disable
feature will prevent your
vehicle from shifting
into fth (5) gear.
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CHECK OIL LEVEL
If your vehicle is equipped with an oil level sensor and
the oil level in the vehicle is low, this message will
appear on the DIC. Check the oil level and correct it as
necessary. You may need to let the vehicle cool or
warm up and cycle the ignition to be sure this message
will clear. Once the problem is corrected, pressing
any of the four DIC buttons, if equipped, will
acknowledge the message and clear it from the DIC
display. If your vehicle is not equipped with the four DIC
buttons, pressing the trip odometer reset stem will
acknowledge the message and clear it from the DIC
display. SeeEngine Oil (Gasoline Engine) on page 5-20
for additional information.
CHECK WASHER FLUID
If the washer uid level is low, this message will
appear on the DIC. SeeWindshield Washer Fluid on
page 5-47. Adding washer uid to the windshield washer
reservoir will clear the message. Pressing any of the
four DIC buttons, if equipped, will acknowledge the
message and clear it from the DIC display. If your
vehicle is not equipped with the four DIC buttons,
pressing the trip odometer reset stem will acknowledge
the message and clear it from the DIC display.
DRIVER DOOR AJAR
If the driver’s door is not fully closed, this message
will appear on the display and you will hear a chime.
Stop and turn off the vehicle, check the door for
obstacles, and close the door again. Check to see if
the message still appears on the DIC. Pressing any of
the four DIC buttons, if equipped, will acknowledge
the message and clear it from the DIC display. If your
vehicle is not equipped with the four DIC buttons,
pressing the trip odometer reset stem will acknowledge
the message and clear it from the DIC display.
ENGINE COOLANT HOT
If the cooling system temperature gets hot, this message
will appear in the DIC. Turn off the air conditioning.
If the message is still on, or if the engine coolant
temperature gage continues to rise, pull the vehicle
over when it is safe to do so. SeeEngine Coolant
Temperature Gage on page 3-42for more information.
Stop the vehicle and let the engine idle in PARK (P),
or FIRST (1) for manual transmissions, to allow
the coolant to reach a safe temperature. This message
will clear when the coolant temperature drops to
safe operating temperature.
3-56
RANGE SHIFT INHIBITED
(Allison Transmission®Only)
If the transmission is unable to shift into a selected
gear, this message will appear on the DIC. The
electronic shift position indicator on the instrument panel
cluster may blink when this occurs. To make the
vehicle shift to the requested gear, you may have to
shift back to PARK (P) or NEUTRAL (N) and re-select
the desired gear.
REDUCED ENGINE POWER
This message is displayed when the cooling system
temperature gets too hot and the engine further enters
the engine coolant protection mode.
SeeEngine Overheating on page 5-38for additional
information.
RIGHT REAR DOOR AJAR (Crew Cab)
If the passenger’s side rear door is not fully closed,
this message will appear on the display and you
will hear a chime. Stop and turn off the vehicle, check
the door for obstacles, and close the door again.
Check to see if the message still appears on the DIC.
Pressing any of the four DIC buttons, if equipped,
will acknowledge the message and clear it from the
DIC display. If your vehicle is not equipped with the
four DIC buttons, pressing the trip odometer reset stem
will acknowledge the message and clear it from the
DIC display.
SERVICE 4WD (Four-Wheel-Drive)
If a problem occurs with the four-wheel-drive system,
this message will appear on the DIC. If this message
appears, stop as soon as possible and turn off the
vehicle. Restart the vehicle and check for the message
on the DIC display. If the message is still displayed
or appears again when you begin driving, the
four-wheel-drive system needs service. See your
GM dealer.
SERVICE 4 WHEEL STEER
If a problem occurs with the four-wheel steer system,
this message will appear on the DIC. If this message
appears, stop as soon as possible and turn off the
vehicle. Restart the vehicle and check for the message
on the DIC display. If the message is still displayed
or appears again when you begin driving, the four-wheel
steer system needs service. See your GM dealer. See
QUADRASTEER™ on page 4-14for more information.
Pressing any of the four DIC buttons, if equipped,
will acknowledge the message and clear it from the
DIC display. If your vehicle is not equipped with the
four DIC buttons, pressing the trip odometer reset stem
will acknowledge the message and clear it from the
DIC display.
3-59