tow GMC SAVANA PASSENGER 2015 Service Manual

Black plate (34,1)GMC Savana Owner Manual (GMNA-Localizing-U.S./Canada-7707482) -
2015 - crc - 6/3/14
9-34 Driving and Operating
Using Cruise Control on Hills
How well cruise control works on
hills depends on the vehicle speed,
load, and the steepness of the hills.
When going up steep hills, you
might have to step on the
accelerator pedal to maintain your
speed.
While going downhill:
.Vehicles with a 4-speed
automatic transmission may
need to have the brakes applied
or the transmission shifted to a
lower gear to help maintain
driver selected speed.
.Vehicles with a 6-speed
automatic transmission have
Cruise Grade Braking to help
maintain driver selected speed.Cruise Grade Braking is enabled
when the vehicle is started and
cruise control is active. It is not
enabled in Range Selection Mode.
It assists in maintaining driver
selected speed when driving on
downhill grades by using the engine
and transmission to slow the
vehicle.
To disable and enable Cruise Grade
Braking for the current ignition key
cycle, press and hold the Tow/Haul
button for three seconds. A DIC
message displays. See
Transmission Messages on
page 5-35.
When the brakes are manually
applied the cruise control is
disengaged.
Ending Cruise Control
There are four ways to end cruise
control:
.Step lightly on the brake pedal.
.Press[.
.Shift the transmission to
N (Neutral).
.To turn off cruise control,
press
I.
Erasing Speed Memory
The cruise control set speed is
erased from memory if
Iis
pressed or if the vehicle is
turned off.

Black plate (35,1)GMC Savana Owner Manual (GMNA-Localizing-U.S./Canada-7707482) -
2015 - crc - 6/3/14
Driving and Operating 9-35
Driver Assistance
Systems
Parking Assist
If available, the Rear Parking Assist
(RPA) system uses sensors on the
rear bumper to assist with parking
and avoiding objects while in
R (Reverse).
{Warning
The parking assist system does
not detect children, pedestrians,
bicyclists, animals, or objects
below the bumper or that are too
close or too far from the vehicle.
It is not available at speeds
greater than 8 km/h (5 mph). To
prevent injury, death, or vehicle
damage, even with parking assist,
always check the area around the
vehicle and check all mirrors
before backing.
How the System Works
RPA comes on automatically when
the shift lever is moved into
R (Reverse). A single beep sounds
to indicate the system is working.
RPA operates only at speeds less
than 8 km/h (5 mph).
An obstacle detection is indicated
by beeps. The time between beeps
gets shorter as the vehicle
approaches the obstacle. Repeated
beeps are heard when the distance
is less than 30 cm (12 in).
To be detected, objects must be at
least 25 cm (10 in) off the ground
and below rear door level. Objects
must also be within 2.5 m (8 ft) from
the rear bumper. This distance may
be less during warmer or humid
weather.
Turning the System On and Off
The system can be disabled through
the Driver Information Center (DIC).
See“Park Assist” underDriver
Information Center (DIC) on
page 5-23. RPA defaults to the on setting each
time the vehicle is started.
Turn RPA off when towing a trailer.
When the System Does Not
Seem to Work Properly
The following messages may be
displayed on the DIC:
SERVICE PARK ASSIST:
If this
message occurs, take the vehicle to
your dealer for repair.
PARK ASSIST OFF: This message
occurs if the driver disables the
system or if the vehicle is driven
above 8 km/h (5 mph) in
R (Reverse).
PARK ASST BLOCKED SEE
OWNERS MANUAL: This
message can occur under the
following conditions:
.The sensors are not clean. Keep
the rear bumper free of mud,
dirt, snow, ice, slush, and frost.
The message may not clear until
frost or ice has melted all around
and inside the sensor.

Black plate (36,1)GMC Savana Owner Manual (GMNA-Localizing-U.S./Canada-7707482) -
2015 - crc - 6/3/14
9-36 Driving and Operating
.A trailer is attached to the
vehicle, or a bicycle or an object
hanging out of the rear door
during the current or last drive
cycle. RPA will return to normal
operation after it is determined
the object is removed. This
could take a few drive cycles.
.A tow bar is attached to the
vehicle.
Other conditions may affect system
performance, such as vibrations
from a jackhammer or the
compression of air brakes on a very
large truck.
Rear Vision
Camera (RVC)
If available, the RVC system is
designed to help the driver when
backing up by displaying a view of
the area behind the vehicle.
{Warning
The RVC system does not display
children, pedestrians, bicyclists,
crossing traffic, animals, or any
other object located outside the
camera's field of view, below the
bumper, or under the vehicle.
Perceived distances may be
different from actual distances.
Do not back the vehicle using
only the RVC screen. Failure to
use proper care before backing
may result in injury, death,
or vehicle damage. Always check
behind and around the vehicle
before backing.
Vehicles without Navigation
System
When the vehicle is on and shifted
into R (Reverse), the video image
appears on the inside rearview
mirror. The video image disappears
after the vehicle is shifted out of
R (Reverse).
Vehicles with Navigation
System
When the vehicle is shifted into
R (Reverse), the video image
appears on the navigation screen.
After a delay, the navigation screen
displays the previous screen after
the vehicle is shifted out of
R (Reverse).
The delay that is received after
shifting out of R (Reverse) is
approximately 10 seconds. Return to
the previous screen sooner by
performing one of the following:
.Press a hard key on the
navigation system.
.Shift into P (Park).
.Reach a vehicle speed of
8 km/h (5 mph).
Symbols and Guidelines
The navigation system may have a
feature that allows for viewing
parking assist symbols and/or
guidelines on the navigation screen
while using the RVC. The Rear Park

Black plate (44,1)GMC Savana Owner Manual (GMNA-Localizing-U.S./Canada-7707482) -
2015 - crc - 6/3/14
9-44 Driving and Operating
Trailer Towing
General Towing
Information
Only use towing equipment that has
been designed for the vehicle.
Contact your dealer or trailering
dealer for assistance with preparing
the vehicle for towing a trailer. Read
the entire section before towing a
trailer.
For towing a disabled vehicle, see
Towing the Vehicle on page 10-77.
For towing the vehicle behind
another vehicle such as a motor
home, seeRecreational Vehicle
Towing on page 10-77.
Driving Characteristics
and Towing Tips
Driving with a Trailer
When towing a trailer:
.Become familiar with the state
and local laws that apply to
trailer towing.
.Do not tow a trailer during the
first 800 km (500 mi) to prevent
damage to the engine, axle,
or other parts.
.Then during the first 800 km
(500 mi) of trailer towing, do not
drive over 80 km/h (50 mph) and
do not make starts at full throttle.
.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.
.Turn off Park Assist when
towing.
{Warning
When towing a trailer, exhaust
gases may collect at the rear of
the vehicle and enter if the
liftgate, trunk/hatch, or rear-most
window is open.
(Continued)
Warning (Continued)
When towing a trailer:
.Do not drive with the liftgate,
trunk/hatch, or rear-most
window open.
.Fully open the air outlets on
or under the instrument
panel.
.Also adjust the climate
control system to a setting
that brings in only outside air.
See“Climate Control
Systems” in the Index.
For more information about
Carbon Monoxide, see Engine
Exhaust on page 9-21.
Towing a trailer requires a certain
amount of experience. The
combination you are driving is
longer and not as responsive as the
vehicle itself. Get acquainted with
the handling and braking of the rig
before setting out for the open road.

Black plate (45,1)GMC Savana Owner Manual (GMNA-Localizing-U.S./Canada-7707482) -
2015 - crc - 6/3/14
Driving and Operating 9-45
Before starting, check all trailer hitch
parts and attachments, safety
chains, electrical connectors, lamps,
tires, and mirrors. If the trailer has
electric brakes, start the
combination moving and then apply
the trailer brake controller by hand
to be sure the brakes work.
During the trip, check occasionally
to be sure that the load is secure
and the lamps and any trailer
brakes still work.
Following Distance
Stay at least twice as far behind the
vehicle ahead as you would when
driving the vehicle without a trailer.
This can help to avoid heavy
braking and sudden turns.
Passing
More passing distance is needed
when towing a trailer. The
combination will not accelerate as
quickly and is longer so it is
necessary to go much farther
beyond the passed vehicle before
returning to the lane.
Backing Up
Hold the bottom of the steering
wheel with one hand. To move the
trailer to the left, move that hand to
the left. To move the trailer to the
right, move your hand to the right.
Always back up slowly and,
if possible, have someone
guide you.
Making Turns
{Caution
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
cluster 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
before starting 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 9-27.
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

Black plate (46,1)GMC Savana Owner Manual (GMNA-Localizing-U.S./Canada-7707482) -
2015 - crc - 6/3/14
9-46 Driving and Operating
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
transmission in P (Park) for a few
minutes before turning the engine
off. If the overheat warning comes
on, seeEngine Overheating on
page 10-18.
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.
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.
4. Reapply the brake pedal. Then apply the parking brake and shift
into P (Park).
5. Release the brake pedal.
Leaving After Parking on a Hill
1. Apply and hold the brake pedal.
2. Start the engine.
3. Shift into a gear.
4. Release the parking brake.
5. Let up on the brake pedal.
6. Drive slowly until the trailer is clear of the chocks. 7. Stop and have someone pick up
and store the chocks.
Maintenance when Trailer
Towing
The vehicle needs service more
often when pulling a trailer. See
Maintenance Schedule on
page 11-3. 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 Towing
If the vehicle has a diesel engine,
see the Duramax diesel
supplement.

Black plate (47,1)GMC Savana Owner Manual (GMNA-Localizing-U.S./Canada-7707482) -
2015 - crc - 6/3/14
Driving and Operating 9-47
{Warning
The driver can lose control when
pulling a trailer if the correct
equipment is not used or the
vehicle is not driven properly. For
example, if the trailer is too
heavy, the brakes may not work
well—or even at all. The driver
and passengers could be
seriously injured. The vehicle may
also be damaged; the resulting
repairs would not be covered by
the vehicle warranty. Pull a trailer
only if all the steps in this section
have been followed. Ask your
dealer for advice and information
about towing a trailer with the
vehicle.
{Caution
Pulling a trailer improperly can
damage the vehicle and result in
costly repairs not covered by the
vehicle warranty. To pull a trailer
correctly, follow the advice in this
section and see your dealer for
important information about
towing a trailer with the vehicle.
To identify the trailering capacity of
the vehicle, read the information in
“Weight of the Trailer” following.
Trailering is different than just
driving the vehicle by itself.
Trailering means changes in
handling, acceleration, braking,
durability, and fuel economy.
Successful, safe trailering takes
correct equipment, and it has to be
used properly.
The following information has many
time-tested, important trailering tips
and safety rules. Many of these are
important for your safety and that of your passengers. So please read
this section carefully before pulling a
trailer.
Weight of the Trailer
How heavy can a trailer safely be?
It depends on how the rig is used.
For example, speed, altitude, road
grades, outside temperature, and
how much the vehicle is used to pull
a trailer are all important. It can
depend on any special equipment
on the vehicle, and the amount of
tongue weight the vehicle can carry.
See
“Weight of the Trailer Tongue”
later in this section.
Maximum trailer weight is calculated
assuming only the driver is in the
tow vehicle and it has all the
required trailering equipment. The
weight of additional optional
equipment, passengers,and cargo in
the tow vehicle must be subtracted
from the maximum trailer weight.

Black plate (49,1)GMC Savana Owner Manual (GMNA-Localizing-U.S./Canada-7707482) -
2015 - crc - 6/3/14
Driving and Operating 9-49
VehicleAxle Ratio Maximum Trailer Weight GCWR*
G3500 Passenger Van 2WD Short Wheelbase 6.0L V8 3.424 400 kg (9,700 lb) 7 257 kg (16,000 lb)
G3500 Passenger Van 2WD Long Wheelbase 6.0L V8 3.424 218 kg (9,300 lb) 7 257 kg (16,000 lb)
*The Gross Combined Weight Rating (GCWR) is the total allowable weight of the completely loaded vehicle and
trailer including any passengers, cargo, equipment, and conversion. The GCWR for the vehicle should not be
exceeded.
Ask your dealer for trailering
information or advice.
Weight of the Trailer Tongue
The tongue load (1) of any trailer is
an important weight to measure
because it affects the total gross
weight of the vehicle. The Gross
Vehicle Weight (GVW) includes the
curb weight of the vehicle, any
cargo carried in it, and the people
who will be riding in the vehicle. If there are a lot of options,
equipment, passengers, or cargo in
the vehicle, it will reduce the tongue
weight the vehicle can carry, which
will also reduce the trailer weight the
vehicle can tow. If towing a trailer,
the tongue load must be added to
the GVW because the vehicle will
be carrying that weight, too. See
Vehicle Load Limits on page 9-9
for
more information about the vehicle's
maximum load capacity.
The trailer tongue weight (1) should
be 10 percent to 15 percent of the
total loaded trailer weight (2), up to a

Black plate (50,1)GMC Savana Owner Manual (GMNA-Localizing-U.S./Canada-7707482) -
2015 - crc - 6/3/14
9-50 Driving and Operating
maximum of 181 kg (400 lb) with a
weight carrying hitch. The trailer
tongue weight (1) should be
10 percent to 15 percent of the total
loaded trailer weight (2), up to a
maximum of 454 kg (1,000 lb) with a
weight distributing hitch.
Do not exceed the maximum
allowable tongue weight for the
vehicle. Choose the shortest hitch
extension that will position the hitch
ball closest to the vehicle. This will
help reduce the effect of trailer
tongue weight on the rear axle.
After loading the trailer, weigh the
trailer and then the tongue,
separately, to see if the weights are
proper. If they are not, adjustments
might be made by moving some
items around in the trailer.
Trailering may be limited by the
vehicle's ability to carry tongue
weight. Tongue weight cannot cause
the vehicle to exceed the GVWR
(Gross Vehicle Weight Rating) or
the RGAWR (Rear Gross Axle
Weight Rating). The effect ofadditional weight may reduce the
trailering capacity more than the
total of the additional weight.
It is important that the vehicle does
not exceed any of its ratings
—
GCWR, GVWR, RGAWR, Maximum
Trailer Rating, or Tongue Weight.
The only way to be sure it is not
exceeding any of these ratings is to
weigh the vehicle and trailer.
Total Weight on the Vehicle's
Tires
Be sure the vehicle tires are inflated
to the upper limit for cold tires.
These numbers can be found on the
Certification label at the rear edge of
the driver door, or see Vehicle Load
Limits on page 9-9. Make sure not
to go over the GVW limit for the
vehicle, or the GAWR, including the
weight of the trailer tongue. If using
a weight distributing hitch, make
sure not to go over the rear axle
limit before applying the weight
distribution spring bars.
Towing Equipment
Hitches
The correct hitch equipment helps
maintain combination control. Many
trailers can be towed with a
weight-carrying hitch which simply
features a coupler latched to the
hitch ball, or a tow eye latched to a
pintle hook. Other trailers may
require a weight-distributing hitch
that uses spring bars to distribute
the trailer tongue weight among the
two vehicle and trailer axles. See
“Weight of the Trailer Tongue” under
Trailer Towing on page 9-46 for
rating limits with various hitch types.
Consider using sway controls with
any trailer. Ask a trailering
professional about sway controls or
refer to the trailer manufacturer's
recommendations and instructions.

Black plate (51,1)GMC Savana Owner Manual (GMNA-Localizing-U.S./Canada-7707482) -
2015 - crc - 6/3/14
Driving and Operating 9-51
Weight-Distributing Hitches
and Weight Carrying Hitches
A weight distributing hitch may be
useful with some trailers. Use the
following guidelines to determine if a
weight distributing hitch should
be used.
1. Body to Ground Distance
2. Front of Vehicle
When using a weight-distributing
hitch, the hitch must be adjusted so
the distance (1) remains the same
both before and after coupling the
trailer to the tow vehicle.
Safety Chains
Always attach chains between the
vehicle and the trailer. Cross the
safety chains under the tongue of
the trailer to help prevent the tongue
from contacting the road if it
becomes separated from the hitch.
Always leave just enough slack so
the rig can turn. Never allow safety
chains to drag on the ground.
Trailer Brakes
A loaded trailer that weighs more
than 680 kg (1,500 lb) 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.
Trailer Wiring Harness
The optional heavy-duty trailer
wiring package includes a wiring
harness, with a seven-pin connector
at the rear of the vehicle and a
four-wire harness assembly under
the driver side of the instrumentpanel. The four-wire harness
assembly comes without a
connector.
If the vehicle does not have a trailer
hitch, the seven-wire harness
assembly with connector is taped
together and located in a frame
pocket at the driver side rear left
corner of the frame.
If the vehicle has a trailer hitch, the
seven-wire harness assembly with
connector is attached to a bracket
on the hitch platform. In both cases,
the seven-wire harness has a
connector and includes a 30-amp
feed wire.
The seven-wire harness connector
contains the following trailer circuits:
.Light Green: Back-up Lamps
(10A fuse)**
.White: Ground
.Dark Blue: Trailer Brake Signal
.Dark Green: Right Rear Stop
and Turn Signal*