2008 CHEVROLET SUBURBAN service

Both the liftglass and liftgate have an electric latch. If
the battery is disconnected or has low voltage, the
liftglass and liftgate will not open. The liftglass
and liftgate will resume operation when the battery is
reconnected and charged.
If the battery is properly connected and has adequate
voltage, and the liftgate or liftglass still will not function,
your vehicle should be taken to a dealership for
service.
Power Liftgate
Power Liftgate Operation
{CAUTION:
It can be dangerous to drive with the liftgate
open because carbon monoxide (CO) gas can
come into your vehicle. You cannot see or
smell CO. It can cause unconsciousness and
even death.
CAUTION: (Continued)
CAUTION: (Continued)
If you must drive with the liftgate open, or if
electrical wiring or other cable connections
must pass through the seal between the body
and the liftgate:
Make sure all other windows are shut.
Turn the fan on your heating or cooling
system to its highest speed with the
recirculation mode off. That will force
outside air into your vehicle. See Climate
Control System in the index.
If you have air outlets on or under the
instrument panel, open them all the way.
If your vehicle has a power liftgate, disable
the power liftgate function.
SeePower Liftgate on page 2-14.
On vehicles with a power liftgate the button is located
on the overhead console.
The vehicle must be in PARK (P) to use the power
liftgate feature.
&:Press the top of the button to open or close the
power liftgate.
2-14

OFF:Press the bottom of the button for manual
operation of the power liftgate.
The taillamps will ash and a chime will sound when the
power liftgate is moving.
{CAUTION:
You or others could be injured if caught in the
path of the power liftgate. Make sure there is
no one in the way of the liftgate as it is
opening and closing.
Notice:If you open the liftgate without checking for
overhead obstructions such as a garage door,
you could damage the liftgate or the liftgate glass.
Always check to make sure the area above and
behind the liftgate is clear before opening it.
The power liftgate can be power opened and closed in
the following ways:
Press and hold the power liftgate button on the
Remote Keyless Entry (RKE) transmitter until
the liftgate starts moving.Remote Keyless Entry
(RKE) System Operation on page 2-5for more
information.
Pressing the liftgate button on the overhead
console.
Pressing the touchpad switch on the outside liftgate
handle.
Pressing the buttons, or touchpad switch a second time
while the liftgate is moving reverses the direction.
l:The liftgate can also be closed by pressing the
power liftgate button next to the liftgate latch.
Press the button a second time during liftgate operation
to reverse that operation.
The power liftgate may be temporarily disabled under
extreme temperatures, or under low battery conditions. If
this occurs, the liftgate can still be operated manually.
If you shift the transmission out of PARK (P) while
the power function is in progress, the liftgate power
function will continue to completion. If you shift the
transmission out of PARK (P) and accelerate before the
power liftgate latches closed, the liftgate may reverse
to the open position. Cargo could fall out of the vehicle.
Always make sure the power liftgate is closed and
latched before you drive away.
If you power open the liftgate and the liftgate support
struts have lost pressure, the lights will ash and a
chime will sound. The liftgate will stay open temporarily,
then slowly close. See your dealer/retailer for service
before using the liftgate.
2-15

If the battery is properly connected with adequate
voltage, the switch is not disabled, and the liftgate still
will not function, your vehicle should be taken to a
dealer/retailer for service.
Power Running Boards
Your vehicle may have power running boards.
The power running boards automatically extend from
beneath the vehicle on the side in which the door
has been opened. Once the door is closed, the running
boards will automatically move back under the vehicle
after a brief delay. The vehicle must not be moving
for the running boards to extend or retract.The switch used to disable
the power running boards
is located on the center
console below the climate
control system.
The running boards cannot be disabled in the extended
position.
2-17

If you set off the alarm by accident, press unlock on the
RKE transmitter or place the key in the ignition and
turn it to START to turn off the alarm. The alarm will not
stop if you try to unlock a door any other way.
Testing the Alarm
To test the alarm:
1. From inside the vehicle, lower the driver’s window
and open the driver’s door.
2. Activate the system by locking the doors with the
power door lock switch while the door is open, or
with the RKE transmitter.
3. Get out of the vehicle, close the door and wait for
the security light to go out.
4. Then reach in through the window, unlock the door
with the manual door lock and open the door. This
should set off the alarm.
While the alarm is set, the power door unlock switch will
not work.
If the alarm does not sound when it should but the
headlamps ash, check to see if the horn works. The
horn fuse may be blown. To replace the fuse, seeFuses
and Circuit Breakers on page 5-119.
If the alarm does not sound or the headlamps do not
ash, the vehicle should be serviced by your
dealer/retailer.
PASS-Key®III+ Electronic
Immobilizer
The PASS-Key III+ system operates on a radio
frequency subject to Federal Communications
Commission (FCC) Rules and with Industry Canada.
This device complies with Part 15 of the FCC Rules.
Operation is subject to the following two conditions:
1. This device may not cause harmful interference.
2. This device must accept any interference received,
including interference that may cause undesired
operation.
This device complies with RSS-210 of Industry Canada.
Operation is subject to the following two conditions:
1. This device may not cause interference.
2. This device must accept any interference received,
including interference that may cause undesired
operation of the device.
Changes or modications to this system by other than
an authorized service facility could void authorization to
use this equipment.
PASS-Key III+ uses a radio frequency transponder in
the key that matches a decoder in the vehicle.
2-22

PASS-Key®III+ Electronic
Immobilizer Operation
Your vehicle has PASS-Key®III+ (Personalized
Automotive Security System) theft-deterrent system.
PASS-Key
®III+ is a passive theft-deterrent system.
The system is automatically armed when the key
is removed from the ignition.
The system is automatically disarmed when the key is
turned to ON/RUN, ACC/ACCESSORY or START
from the LOCK/OFF position.
You do not have to manually arm or disarm the system.
The security light will come on if there is a problem
with arming or disarming the theft-deterrent system.
When the PASS-Key
®III+ system senses that someone
is using the wrong key, it prevents the vehicle from
starting. Anyone using a trial-and-error method to start
the vehicle will be discouraged because of the high
number of electrical key codes.
If the engine does not start and the security light on the
instrument panel cluster comes on when trying to
start the vehicle, there may be a problem with your
theft-deterrent system. Turn the ignition off and try again.If the engine still does not start, and the key appears to
be undamaged, try another ignition key. At this time,
you may also want to check the fuse, seeFuses
and Circuit Breakers on page 5-119. If the engine still
does not start with the other key, your vehicle needs
service. If your vehicle does start, the rst key may be
faulty. See your dealer/retailer who can service the
PASS-Key
®III+ to have a new key made. In an
emergency, contact Roadside Assistance.
It is possible for the PASS-Key
®III+ decoder to learn
the transponder value of a new or replacement key. Up
to 10 keys may be programmed for the vehicle. The
following procedure is for programming additional keys
only. If all the currently programmed keys are lost or
do not operate, you must see your dealer/retailer
or a locksmith who can service PASS-Key
®III+ to have
keys made and programmed to the system.
See your dealer/retailer or a locksmith who can service
PASS-Key
®III+ to get a new key blank that is cut
exactly as the ignition key that operates the system.
2-23

To program the new additional key:
1. Verify that the new key has a
1stamped on it.
2. Insert the original, already programmed, key in the
ignition and start the engine. If the engine will not
start, see your dealer/retailer for service.
3. After the engine has started, turn the key to
LOCK/OFF, and remove the key.
4. Insert the new key to be programmed and turn it to
the ON/RUN position within ve seconds of turning
the ignition to the LOCK/OFF position in Step 3.
The security light will turn off once the key has been
programmed.
5. Repeat Steps 1 through 4 if additional keys are to
be programmed.
If you lose or damage your PASS-Key
®III+ key, see
your dealer/retailer or a locksmith who can service
PASS-Key
®III+ to have a new key made.
Do not leave the key or device that disarms or
deactivates the theft deterrent system in the vehicle.
Starting and Operating Your
Vehicle
New Vehicle Break-In
Notice:Your vehicle does not need an elaborate
break-in. But it will perform better in the long run if
you follow these guidelines:
Keep your speed at 55 mph (88 km/h) or less for
the rst 500 miles (805 km).
Do not drive at any one constant speed, fast or
slow, for the rst 500 miles (805 km). Do not
make full-throttle starts. Avoid downshifting to
brake or slow the vehicle.
Avoid making hard stops for the rst 200 miles
(322 km) or so. During this time the new brake
linings are not yet broken in. Hard stops
with new linings can mean premature wear and
earlier replacement. Follow this breaking-in
guideline every time you get new brake linings.
Do not tow a trailer during break-in. SeeTowing
a Trailer on page 4-49for the trailer towing
capabilities of your vehicle and more
information.
Following break-in, engine speed and load can be
gradually increased.
2-24

Ignition Positions
Use the key to turn the
ignition switch to four
different positions.
In order to shift out of PARK (P), ignition must be in the
ON/RUN or ACC/ACCESSORY and the regular brake
pedal must be applied.
A (LOCK/OFF):This position locks the ignition and
transmission. It is a theft-deterrent feature. The key
can only be removed when the ignition is turned
to LOCK/OFF.Notice:Using a tool to force the key from the
ignition switch could cause damage or break the
key. Use the correct key and turn the key only with
your hand. Make sure the key is all the way in. If
it is, turn the steering wheel left and right while you
turn the key hard. If none of this works, then
your vehicle needs service.
B (ACC/ACCESSORY):This position lets things like
the radio and the windshield wipers operate while
the engine is off.
Lengthy operation of features such as the radio in the
ACC/ACCESSORY ignition position and the ON/RUN
position may drain the battery and prevent your vehicle
from starting. Do not operate your vehicle in the ACC/
ACCESSORY ignition position for a long period of time.
C (ON/RUN):This is the position for driving. It is the
position the ignition switch returns to after the engine
starts, and the key is released.
The battery could be drained if you leave the key in the
ACC/ACCESSORY or ON/RUN position with the engine
off. You may not be able to start your vehicle if the battery
is allowed to drain for an extended period of time.
D (START):This position starts the engine.
2-25

Front Axle
The front axle engages and disengages automatically
when you shift the transfer case. Some delay for
the axle to engage or disengage is normal.
Automatic Transfer Case
The transfer case knob is
located to the left of the
instrument panel cluster.
Your vehicle has Four Wheel Drive with StabiliTrak
®.
For information on StabiliTrak®, seeStabiliTrak®System
on page 4-6.
Use this dial to shift into and out of four-wheel drive.You can choose among ve driving settings:
Indicator lights in the switches show you which setting
you are in. The indicator lights will come on briey when
you turn on the ignition and the last chosen setting
will stay on. If the lights do not come on, you should take
your vehicle in for service. An indicator light will ash
while shifting. Fast ashing means the conditions
were not met to make the desired shift, typically the
vehicle was going too fast, the automatic transmission
was not in neutral. Slow ashing means the shift is
in progress. It will stay on when the shift is completed.
If for some reason the transfer case cannot make a
requested shift, it will return to the last chosen setting.
2
m(Two-Wheel Drive High):This setting is used for
driving in most street and highway situations. Your
front axle is not engaged in two-wheel drive. This setting
also provides the best fuel economy.
AUTO (Automatic Four-Wheel Drive):This setting is
ideal for use when road surface traction conditions
are variable. When driving your vehicle in AUTO, the
front axle is engaged, but the vehicle’s power is primarily
sent to the rear wheels. When the vehicle’s software
determines a need for more traction, the system
will transfer more power to the front wheels. Driving in
this mode results in slightly lower fuel economy than
Two-Wheel Drive High.
2-37