2008 GMC SAVANA PASSENGER ECU

Dolly Towing
Rear Towing (Rear Wheels Off the Ground)
Two-Wheel-Drive Vehicles
Use the following procedure to tow your vehicle from
the rear:
1. Drive the vehicle onto the dolly.
2. Firmly set the parking brake. SeeParking Brake on
page 2-26for more information.
3. Put the automatic transmission in PARK (P).
4. Follow the dolly manufacturer’s instructions to attach
and secure the vehicle being towed to the dolly and
then the loaded dolly to the tow vehicle. Make sure
the wheels are straight before towing.
Use an adequate clamping device to ensure that
the front wheels are locked into the straight position.5. Release the parking brake only after the vehicle
being towed is firmly attached to the tow vehicle.
6. Turn the ignition to LOCK/OFF.
If the tow vehicle will not be started or driven for
six weeks or more, remove the battery cable
from the negative terminal (post) of the battery to
prevent your battery from draining while towing.
All-Wheel-Drive Vehicles
Your vehicle was not designed to be towed with two
wheels on the ground. To properly tow these vehicles,
they should be placed on a platform trailer with all
four wheels off the ground.
Notice:Towing an all-wheel-drive vehicle with all
four wheels on the ground, or even with only two of
its wheels on the ground, will damage drivetrain
components. Do not tow an all-wheel-drive vehicle if
any of its wheels will be on the ground.
4-27

G3500 Cargo Van 2WD
Long WheelbaseAxle Ratio Maximum Trailer Weight GCWR*
4800 V83.73
4.106,100 lbs (2 767 kg)
7,100 lbs (3 221 kg)12,000 lbs (5 443 kg)
13,000 lbs (5 897 kg)
6000 V83.73
4.108,200 lbs (3 719 kg)
10,000 lbs (4 536 kg)14,000 lbs (6 350 kg)
16,000 lbs (7 257 kg)
G3500 Passenger Van
2WD Short WheelbaseAxle Ratio Maximum Trailer Weight GCWR*
6000 V8 3.73 7,600 lbs (3 447 kg) 14,000 lbs (6 350 kg)
G3500 Passenger Van
2WD Long WheelbaseAxle Ratio Maximum Trailer Weight GCWR*
6000 V8 3.73 7,300 lbs (3 311 kg) 14,000 lbs (6 350 kg)
*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 your vehicle should not
be exceeded.Ask your dealer/retailer for our trailering information
or advice, or write us at our Customer Assistance
Offices. SeeCustomer Assistance Offices on page 7-5
for more information.
4-32

Driving with a Trailer
{CAUTION:
If you have a rear-most window open and you
pull a trailer with your vehicle, carbon monoxide
(CO) could come into your vehicle. You can not
see or smell CO. It can cause unconsciousness
or death. SeeEngine Exhaust on page 2-30.
To maximize your safety when towing a trailer:
Have your exhaust system inspected for
leaks, and make necessary repairs before
starting on your trip.
Keep the rear-most windows closed.
If exhaust does come into your vehicle
through a window in the rear or another
opening, drive with your front, main heating
or cooling system on and with the fan on
any speed. This will bring fresh, outside air
into your vehicle. Do not use the climate
control setting for maximum air because it
only recirculates the air inside your vehicle.
See Climate Control System in the Index.Towing a trailer requires a certain amount of experience.
Before setting out for the open road, you’ll want to get
to know your rig. Acquaint yourself with the feel of
handling and braking with the added weight of the trailer.
And always keep in mind that the vehicle you are
driving is now a good deal longer and not nearly
as responsive as your vehicle is by itself.
Before you start, check all trailer hitch parts and
attachments, safety chains, electrical connector, lamps,
tires and mirror adjustment. If the trailer has electric
brakes, start your vehicle and trailer moving and then
apply the trailer brake controller by hand to be sure
the brakes are working. This lets you check your
electrical connection at the same time.
During your trip, check occasionally to be sure that the
load is secure, and that the lamps and any trailer
brakes are still working.
Following Distance
Stay at least twice as far behind the vehicle ahead as
you would when driving your vehicle without a trailer.
This can help you avoid situations that require
heavy braking and sudden turns.
4-38

Radiator Pressure Cap
The radiator pressure cap is located near the center of
the engine compartment. SeeEngine Compartment
Overview on page 5-14for more information on location.
Notice:If the pressure cap is not tightly installed,
coolant loss and possible engine damage may
occur. Be sure the cap is properly and tightly
secured.
Engine Overheating
If your vehicle has the DURAMAX®Diesel engine, see
the DURAMAX®Diesel manual for more information.
You will find an engine coolant temperature gage on
your vehicle’s instrument panel. SeeEngine Coolant
Temperature Gage on page 3-35for more information.
If Steam Is Coming From Your Engine
{CAUTION:
Steam from an overheated engine can burn
you badly, even if you just open the hood. Stay
away from the engine if you see or hear steam
coming from it. Just turn it off and get
everyone away from the vehicle until it cools
down. Wait until there is no sign of steam or
coolant before you open the hood.
If you keep driving when your engine is
overheated, the liquids in it can catch re. You
or others could be badly burned. Stop your
engine if it overheats, and get out of the
vehicle until the engine is cool.
Notice:If your engine catches re because you
keep driving with no coolant, your vehicle can be
badly damaged. The costly repairs would not be
covered by your warranty.
5-26

If your vehicle has dual rear wheels, always use
one of the correct rotation patterns shown here
when rotating the tires.
When you install dual wheels, be sure that vent
holes in the inner and outer wheels on each side
are lined up.
After the tires have been rotated, adjust the front
and rear inflation pressures as shown on the Tire
and Loading Information label. SeeInflation - Tire
Pressure on page 5-60andLoading Your Vehicle
on page 4-20. Make certain that all wheel nuts are
properly tightened. See “Wheel Nut Torque” under
Capacities and Specifications on page 5-110.
{CAUTION:
Rust or dirt on a wheel, or on the parts to
which it is fastened, can make wheel nuts
become loose after time. The wheel could
come off and cause an accident. When
you change a wheel, remove any rust or
dirt from places where the wheel attaches
to the vehicle. In an emergency, you can
use a cloth or a paper towel to do this; but
be sure to use a scraper or wire brush later,
if needed, to get all the rust or dirt off. See
Changing a Flat Tire on page 5-78.
If your vehicle has a Tire Pressure Monitor
System (TPMS), reset the TPMS sensors after
rotating the tires. SeeTire Pressure Monitor
Operation on page 5-64.
Make sure the spare tire is stored securely. Push,
pull, and then try to rotate or turn the tire. If it
moves, tighten the cable. SeeStoring a Flat or
Spare Tire and Tools on page 5-93.
Dual Rear Wheels
5-69

Tire Chains
{CAUTION:
If your vehicle has dual wheels or P245/75R16
or LT245/75R16 size tires, do not use tire
chains. They can damage your vehicle because
there is not enough clearance. Tire chains
used on a vehicle without the proper amount of
clearance can cause damage to the brakes,
suspension, or other vehicle parts. The area
damaged by the tire chains could cause you to
lose control of your vehicle and you or others
may be injured in a crash.
Use another type of traction device only if its
manufacturer recommends it for use on your
vehicle and tire size combination and road
CAUTION: (Continued)
CAUTION: (Continued)
conditions. Follow that manufacturer’s
instructions. To help avoid damage to your
vehicle, drive slowly, readjust, or remove the
device if it is contacting your vehicle, and do
not spin the vehicle’s wheels.
If you do nd traction devices that will t,
install them on the rear tires.
Notice:If your vehicle does not have dual wheels
and has a tire size other than P245/75R16 or
LT245/75R16, use tire chains only where legal and
only when you must. Use chains that are the proper
size for your tires. Install them on the tires of the
rear axle. Do not use chains on the tires of the front
axle. Tighten them as tightly as possible with the
ends securely fastened. Drive slowly and follow the
chain manufacturer’s instructions. If you can hear
the chains contacting your vehicle, stop and
retighten them. If the contact continues, slow down
until it stops. Driving too fast or spinning the wheels
with chains on will damage your vehicle.
5-76

The following information tells you how to use the jack
and change a tire.
Removing the Spare Tire and Tools
If you have a cargo van or a passenger van, the
equipment you will need is located in the passenger
side rear corner of the vehicle.
Remove the retaining wing
bolt and lift it off of the
mounting bracket.
If you have a van with the 15-passenger seating
arrangement, the equipment you will need is secured on
the rear floor of the passenger side of the vehicle.
5-79

Storing a Flat or Spare Tire and
Tools
{CAUTION:
Storing a jack, a tire, or other equipment in the
passenger compartment of the vehicle could
cause injury. In a sudden stop or collision,
loose equipment could strike someone. Store
all these in the proper place.
1. Put the tire on the ground at the rear of the vehicle
with the valve stem pointed down.2. Pull the retaining bar through the center of the
wheel, making sure it is properly attached.
3. Pull the wheel toward the rear of the vehicle,
keeping the cable tight.
4. With the UP side facing you, attach the ratchet to
the wheel wrench.
5. Put the flat end of the wheel wrench on an angle
through the hole in the rear door frame, above the
bumper.
6. Raise the tire fully against the underside of the
vehicle. Continue turning the ratchet until the tire
is secure and the cable is tight. The spare tire hoist
cannot be overtightened.
5-93