automatic transmission GMC SIERRA 1500 2009 Owner's Manual
[x] Cancel search | Manufacturer: GMC, Model Year: 2009, Model line: SIERRA 1500, Model: GMC SIERRA 1500 2009Pages: 602, PDF Size: 3.22 MB
Page 334 of 602

It is recommended to leave the system on for normal
driving conditions, but it may be necessary to turn
the system off if the vehicle is stuck in sand, mud, ice or
snow, and you want to “rock” the vehicle to attempt to
free it. It may also be necessary to turn off the
system when driving in extreme off-road conditions
where high wheel spin is required. SeeIf Your Vehicle
is Stuck in Sand, Mud, Ice, or Snow on page 4-32
When the transfer case is in 4LO, the stability system is
automatically disabled, the StabiliTrak light comes on
and the STABILITRAK OFF message will appear
on the DIC. Both traction control and StabiliTrak are
automatically disabled in this condition.
Traction Control Operation
The traction control system is part of the StabiliTrak
system. Traction control limits wheel spin by reducing
engine power to the wheels (engine speed management)
and by applying brakes to each individual wheel
(brake-traction control) as necessary.
The traction control system is enabled automatically
when the vehicle is started. It will activate and the
StabiliTrak light will ash if it senses that any of the
wheels are spinning or beginning to lose traction
while driving. If traction control is turned off, only the
brake-traction control portion of traction control will work.The engine speed management will be disabled. 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 ash and cruise
control will automatically disengage. Cruise control may
be reengaged when road conditions allow. SeeCruise
Control on page 3-12.
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.
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Page 405 of 602

Driving On Grades
Reduce speed and shift to a lower gearbeforestarting
down a long or steep downgrade. If the transmission is
not shifted down, the brakes might have to be used so
much that they would 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. SeeTow/Haul Mode Light on page 3-51.
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 5-36.
Parking on Hills
{CAUTION:
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
at 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.
2. Have someone place chocks under the trailer
wheels.
3. When the wheel chocks are in place, release the
regular brakes until the chocks absorb the load.
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Page 407 of 602

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
uid, 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.
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