automatic transmission GMC SIERRA 2010 User Guide

If the vehicle has StabiliTrak®, shifting into
Four-Wheel-Drive Low will turn Traction Control and
StabiliTrak
®off. See StabiliTrak®System on page 5‑6.
{WARNING:
Shifting the transfer case to N (Neutral) can cause
the vehicle to roll even if the transmission is in
P (Park). You or someone else could be seriously
injured. Be sure to set the parking brake before
placing the transfer case in N (Neutral). See
Parking Brake on page 3‑50.
N (Neutral) : Shift the vehicle's transfer case to
N (Neutral) only when towing the vehicle. See
Recreational Vehicle Towing
on page 5‑43or Towing
Your Vehicleon page 5‑43for more information.
If the SERVICE 4–Wheel Drive message stays on,
you should take the vehicle to your dealer/retailer for
service. See “Service 4–Wheel Drive message” under
DIC Warnings and Messages on page 4‑65.
Shifting Into Four-Wheel-Drive High or
AUTO (Automatic Four-Wheel Drive)
Turn the knob to the Four-Wheel-Drive High or AUTO
position. This can be done at any speed, except when
shifting from Four-Wheel-Drive Low. The indicator light
will flash while shifting. It will remain on when the shift is
completed.
Shifting Into Two-Wheel-Drive High
Turn the knob to the Two-Wheel-Drive High position.
This can be done at any speed, except when shifting
from Four-Wheel-Drive Low. The indicator light will
flash while shifting. It will remain on when the shift is
completed.
Shifting Into Four-Wheel-Drive Low
When Four-Wheel-Drive Low is engaged, vehicle speed
should be kept below 45 mph. Extended high-speed
operation in Four-Wheel-Drive Low may damage or
shorten the life of the drivetrain.
To shift to the Four-Wheel-Drive Low position, the
ignition must be in ON/RUN and the vehicle must be
stopped or moving less than 3 mph (5 km/h) with the
transmission in N (Neutral). The preferred method for
shifting into Four-Wheel-Drive Low is to have the
vehicle moving 1 to 2 mph (1.6 to 3.2 km/h). Turn the
knob to the Four-Wheel-Drive Low position.
3-47

Running the Vehicle While Parked
It is better not to park with the engine running. But if you
ever have to, here are some things to know.
{WARNING:
Idling a vehicle in an enclosed area with poor
ventilation is dangerous. Engine exhaust may
enter the vehicle. Engine exhaust contains
Carbon Monoxide (CO) which cannot be seen or
smelled. It can cause unconsciousness and even
death. Never run the engine in an enclosed area
that has no fresh air ventilation. For more
information, seeEngine Exhaust on page 3‑54.
{WARNING:
It can be dangerous to get out of the vehicle if the
automatic transmission shift lever is not fully in
P (Park) with the parking brake firmly set. The
vehicle can roll. Do not leave the vehicle when the
engine is running unless you have to. If you have
(Continued)
WARNING: (Continued)
left the engine running, the vehicle can move
suddenly. You or others could be injured. To be
sure the vehicle will not move, even when you are
on fairly level ground, always set the parking
brake and move the shift lever to P (Park).
{WARNING:
Four-wheel drive vehicles with the transfer case in
N (Neutral) will allow the vehicle to roll, even if the
automatic transmission shift lever is in P (Park).
So, be sure the transfer case is in a drive
gear—not in N (Neutral). Always set the
parking brake.
Follow the proper steps to be sure the vehicle will not
move. See Shifting Into Park on page 3‑51.
If pulling a trailer, see Towing a Trailer on page 5‑50.
3-55

Cruise Control
{WARNING:
Cruise control can be dangerous where you
cannot drive safely at a steady speed. So, do not
use the cruise control on winding roads or in
heavy traffic.
Cruise control can be dangerous on slippery
roads. On such roads, fast changes in tire traction
can cause excessive wheel slip, and you could
lose control. Do not use cruise control on slippery
roads.
For vehicles with cruise control, a speed of about
40 km/h (25 mph) or more can be maintained without
keeping your foot on the accelerator. Cruise control
does not work at speeds below about 40 km/h (25 mph). When the brakes are applied, cruise control is
turned off.
For vehicles with an Allison
®or Hydra‐Matic 6‐speed
automatic transmission, see “Grade Braking and Cruise
Grade Braking (Allison Transmission) under Tow/Haul
Mode
on page 3‑34for an explanation of how cruise
control interacts with the Range Selection Mode,
tow/haul and grade braking systems.
For vehicles with the StabiliTrak
®system that begins
to limit wheel spin while you are using cruise control,
the cruise control will automatically disengage.
See StabiliTrak
®Systemon page 5‑6. When road
conditions allow the cruise control to be safely used
again, it can be turned back on.
4-7

Daytime Running Lamps (DRL)
Daytime Running Lamps (DRL) can make it easier for
others to see the front of your vehicle during the day.
Fully functional daytime running lamps are required on
all vehicles first sold in Canada.
The DRL system comes on when the following
conditions are met:
.The ignition is on.
.The exterior lamps control is in AUTO.
.The engine is running.
.The light sensor determines it is daytime.
When the DRL system is on, only the DRL lamps are
on. The taillamps, sidemarker, instrument panel lights,
and other lamps will not be on.
When it begins to get dark, the automatic headlamp
system switches from DRL to the headlamps.
To turn off the DRL lamps, turn the exterior lamps
control to the OFF position and then release.
For vehicles first sold in Canada, the transmission
must be in the P (Park) position, before the DRL lamps
can be turned off.
Automatic Headlamp System
When it is dark enough outside, the automatic
headlamp system turns on the headlamps at the normal
brightness, along with the taillamps, sidemarker, parking
lamps, and the instrument panel lights. The radio lights
will also be dim.
To turn off the automatic headlamp system, turn the
exterior lamps switch to the off position and then
release it. For vehicles first sold in Canada, the
transmission must be in the P (Park) position, before
the automatic headlamp system can be turned off.
The vehicle has a light sensor located on the top of the
instrument panel in the defroster grille that regulates
when the automatic headlamps turn on. Do not cover
the sensor or the headlamps will come on whenever the
ignition is on.
The system may also turn on the headlamps when
driving through a parking garage or heavy overcast
weather. This is normal.
There is a delay in the transition between the daytime
and nighttime operation of the Daytime Running Lamps
(DRL) and the automatic headlamp systems so that
driving under bridges or bright overhead street lights
does not affect the system. The DRL and automatic
headlamp system is only affected when the light sensor
detects a change in lighting lasting longer than the
delay.
4-12

Fuel Used
Press the trip/fuel button until FUEL USED displays.
This display shows the number of gallons (gal) or
liters (L) of fuel used since the last reset of this menu
item. To reset the fuel used information, press and hold
the set/reset button while FUEL USED is displayed.
Timer
Press the trip/fuel button until TIMER displays.
This display can be used as a timer.
To start the timer, press the set/reset button while
TIMER is displayed. The display will show the amount
of time that has passed since the timer was last reset,
not including time the ignition is off. Time will continue
to be counted as long as the ignition is on, even if
another display is being shown on the DIC.
The timer will record up to 99 hours, 59 minutes
and 59 seconds (99:59:59) after which the display
will return to zero.
To stop the timer, press the set/reset button briefly
while TIMER is displayed.
To reset the timer to zero, press and hold the set/reset
button while TIMER is displayed.
Transmission Temperature
Press the trip/fuel button until TRANS TEMP displays.
This display shows the temperature of the automatic
transmission fluid in either degrees Fahrenheit (°F) or
degrees Celsius (°C).
Instantaneous Economy and Active Fuel
Management™Indicator
If your vehicle has this display, press the trip/fuel button
until INST ECON V8 displays. This display shows the
current fuel economy at a particular moment and will
change frequently as driving conditions change. This
display shows the instantaneous fuel economy in miles
per gallon (mpg) or liters per 100 kilometers (L/100 km).
Unlike average economy, this screen cannot be reset.
An Active Fuel Management indicator will display on the
right side of the DIC, while INST ECON displays on the
left side. Active Fuel Management allows the engine to
operate on either four or eight cylinders, depending on
your driving demands. When Active Fuel Management
is active, V4 will display on the DIC. When Active Fuel
Management is inactive, V8 will display. See Active
Fuel Management™
on page 3‑27for more
information.
Blank Display
This display shows no information.
4-54

Transmission Temperature
Press the trip odometer reset stem until TRANS TEMP
displays. This display shows the temperature of the
automatic transmission fluid in either degrees
Fahrenheit (°F) or degrees Celsius (°C).
Trailer Gain and Output
On vehicles with the Integrated Trailer Brake
Control (ITBC) system, the trailer brake display
appears in the DIC. Press the trip odometer reset
stem until TRAILER GAIN and OUTPUT display.
TRAILER GAIN shows the trailer gain setting. This
setting can be adjusted from 0.0 to 10.0 with either a
trailer connected or disconnected. To adjust this setting,
see“Integrated Trailer Brake Control System” under
Towing a Trailer
on page 5‑50for more information.
OUTPUT shows the power output to the trailer anytime
a trailer with electric brakes is connected. Output is
displayed in 0 to 10 bars. Dashes may appear in the
OUTPUT display. See “Integrated Trailer Brake Control
System” underTowing a Trailer
on page 5‑50for
more information.
Compass Zone Setting
This display allows for setting the compass zone.
See DIC Compasson page 4‑62for more information.
Compass Recalibration
This display allows for calibrating the compass.
SeeDIC Compasson page 4‑62for more information.
Oil Life
To access this display, the vehicle must be in P (Park).
Press the trip odometer reset stem until OIL LIFE
REMAINING displays. This display shows an estimate
of the oil's remaining useful life. If you see 99% OIL
LIFE REMAINING on the display, that means 99% of
the current oil life remains. The engine oil life system
will alert you to change the oil on a schedule consistent
with your driving conditions.
When the remaining oil life is low, the CHANGE
ENGINE OIL SOON message will appear on the
display. See “CHANGE ENGINE OIL SOON” underDIC
Warnings and Messages
on page 4‑65. You should
change the oil as soon as you can. See Engine Oilon
page 6‑18. In addition to the engine oil life system
monitoring the oil life, additional maintenance is
recommended in the Maintenance Schedule in this
manual. See Scheduled Maintenance
on page 7‑3for more information.
4-60

In this mode, engine power is not reduced automatically
and the driven wheels can spin more freely. This can
cause the brake-traction control to activate constantly.
Notice:If the wheel(s) of one axle is allowed to spin
excessively while the StabiliTrak, ABS and brake
warning lights and any relevant DIC messages are
displayed, the transfer case could be damaged.
The repairs would not be covered by the vehicle
warranty. Reduce engine power and do not spin the
wheel(s) excessively while these lights and
messages are displayed.
The traction control system may activate on dry or
rough roads or under conditions such as heavy
acceleration while turning or abrupt upshifts/downshifts
of the transmission. When this happens, a reduction in
acceleration may be noticed, or a noise or vibration may
be heard. This is normal.
If cruise control is being used when the system
activates, the StabiliTrak light will flash and cruise
control will automatically disengage. Cruise control may
be reengaged when road conditions allow. See Cruise
Control on page 4‑7.
StabiliTrak may also turn off automatically if it
determines that a problem exists with the system.
If the problem does not clear itself after restarting the
vehicle, see your dealer/retailer for service.Locking Rear Axle
Vehicles with a locking rear axle can give more traction
on snow, mud, ice, sand or gravel. It works like a
standard axle most of the time, but when traction is low,
this feature will allow the rear wheel with the most
traction to move the vehicle.
Steering
Power Steering
If the vehicle is a Two‐mode Hybrid, see the Two‐mode
Hybrid manual for more information.
If power steering assist is lost because the engine stops
or the system is not functioning, the vehicle can be
steered but it will take more effort.
Steering Tips
It is important to take curves at a reasonable speed.
Traction in a curve depends on the condition of the tires
and the road surface, the angle at which the curve is
banked, and vehicle speed. While in a curve, speed is
the one factor that can be controlled.
If there is a need to reduce speed, do it before entering
the curve, while the front wheels are straight.
5-8

vehicle is unloaded. Such a selection when unloaded
may result in unpleasant engine and transmission
driving characteristics and reduced fuel economy.
Tow/Haul is recommended only when pulling a heavy
trailer or a large or heavy load.
Trailer Brakes
A loaded trailer that weighs more than 2,000 lbs
(900 kg) needs to have its own brake system that is
adequate for the weight of the trailer. Be sure to read
and follow the instructions for the trailer brakes so they
are installed, adjusted and maintained properly.
If the vehicle is equipped with StabiliTrak
®, the trailer
cannot tap into the vehicle's hydraulic brake system.
The trailer brake system can tap into the vehicle's
hydraulic brake system only if:
.The trailer parts can withstand 3,000 psi
(20 650 kPa) of pressure.
.The trailer's brake system will use less than
0.02 cubic inch (0.3 cc) of fluid from the vehicle's
master cylinder. Otherwise, both braking systems
will not work well or at all.
If everything checks out this far, make the brake tap at
the port on the master cylinder that sends the fluid to
the rear brakes. Use only steel brake tubing to make
the tap.
Integrated Trailer Brake Control System
The vehicle may have an
Integrated Trailer Brake
Control (ITBC) system for
electric trailer brakes.
This symbol is located on the Trailer Brake Control
Panel on vehicles with an Integrated Trailer Brake
Control System. The power output to the trailer brakes
is based on the amount of brake pressure being applied
by the vehicle’ s brake system. This available power
output to the trailer brakes can be adjusted to a wide
range of trailering situations.
The ITBC system is integrated with the vehicle’s brake,
anti‐lock brake and StabiliTrak (if equipped) systems.
In trailering conditions that cause the vehicle’s anti‐lock
brake or StabiliTrak systems to activate, power sent to
the trailer's brakes will be automatically adjusted to
minimize trailer wheel lock-up. This does not imply that
the trailer has the StabiliTrak system.
5-64

Making Turns
Notice:Making very sharp turns while trailering
could cause the trailer to come in contact with the
vehicle. The vehicle could be damaged. Avoid
making very sharp turns while trailering.
When turning with a trailer, make wider turns than
normal. Do this so the trailer will not strike soft
shoulders, curbs, road signs, trees or other objects.
Avoid jerky or sudden maneuvers. Signal well in
advance.
If the trailer turn signal bulbs burn out, the arrows on the
instrument panel will still flash for turns. It is important to
check occasionally to be sure the trailer bulbs are still
working.
Driving On Grades
Reduce speed and shift to a lower gear beforestarting
down a long or steep downgrade. If the transmission is
not shifted down, the brakes might get hot and no
longer work well.
Vehicles can tow in D (Drive). Shift the transmission to
a lower gear if the transmission shifts too often under
heavy loads and/or hilly conditions.
The tow/haul mode may be used if the transmission
shifts too often. See Tow/Haul Mode on page 3‑34. When towing at high altitude on steep uphill grades,
consider the following: Engine coolant will boil at a
lower temperature than at normal altitudes. If the engine
is turned off immediately after towing at high altitude on
steep uphill grades, the vehicle may show signs similar
to engine overheating. To avoid this, let the engine run
while parked, preferably on level ground, with the
automatic transmission in P (Park) for a few minutes
before turning the engine off. If the overheat warning
comes on, see
Engine Overheating on page 6‑34.
Parking on Hills
{WARNING:
Parking the vehicle on a hill with the trailer
attached can be dangerous. If something goes
wrong, the rig could start to move. People can be
injured, and both the vehicle and the trailer can be
damaged. When possible, always park the rig on
a flat surface.
If parking the rig on a hill: 1. Press the brake pedal, but do not shift into P (Park) yet. Turn the wheels into the curb if facing downhill
or into traffic if facing uphill.
5-72

Maintenance When Trailer Towing
The vehicle needs service more often when pulling a
trailer. See this manual's Maintenance Schedule or
Index for more information. Things that are especially
important in trailer operation are automatic transmission
fluid, engine oil, axle lubricant, belts, cooling system
and brake system. It is a good idea to inspect these
before and during the trip.
Check periodically to see that all hitch nuts and bolts
are tight.
Trailer Wiring Harness
The vehicle is equipped with one of the following wiring
harnesses for towing a trailer or hauling a slide-in
camper.
Basic Trailer Wiring
All regular, extended cab and crew cab pickups have a
seven‐wire trailer towing harness.
For vehicles not equipped with heavy duty trailering, the
harness is secured to the vehicle's frame behind the
spare tire mount. The harness requires the installation
of a trailer connector, which is available through your
dealer/retailer.
If towing a light‐duty trailer with a standard four‐way
round pin connector, an adapter is available from your
dealer/retailer.
Heavy-DutyTrailer Wiring Harness
Package
For vehicles equipped with heavy duty trailering, the
harness is connected to a bracket on the hitch platform.
The seven-wire harness contains the following trailer
circuits:
.Yellow: Left Stop/Turn Signal
.Dark Green: Right Stop/Turn Signal
.Brown: Taillamps
.White: Ground
.Light Green: Back-up Lamps
.Red: Battery Feed*
.Dark Blue: Trailer Brake*
5-74