engine CHEVROLET EXPRESS 2012 Workshop Manual

Black plate (16,1)Chevrolet Express Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
7707481) - 2015 - CRC - 4/30/14
9-16 Driving and Operating
If you leave the key in the ACC/
ACCESSORY or ON/RUN position
with the engine off, the battery could
be drained. You may not be able to
start the vehicle if the battery is
allowed to drain for an extended
period of time.
4 (START):This is the position that
starts the engine. When the engine
starts, release the key. The ignition
switch returns to ON/RUN for
driving.
A warning tone will sound when the
driver door is opened, the ignition is
in ACC/ACCESSORY or LOCK/OFF
and the key is in the ignition.
Starting the Engine
If the vehicle has a diesel engine,
see the Duramax diesel
supplement. To place the transmission in the
proper gear:
Move the shift lever to P (Park) or
N (Neutral). The engine will not start
in any other position. To restart the
engine when the vehicle is already
moving, use N (Neutral) only.
{Caution
If you add electrical parts or
accessories, you could change
the way the engine operates. Any
resulting damage would not be
covered by the vehicle warranty.
See
Add-On Electrical Equipment
on page 9-54.
{Caution
Do not try to shift to P (Park) if the
vehicle is moving. If you do, you
could damage the transmission.
Shift to P (Park) only when the
vehicle is stopped.
{Caution
If the steering wheel is turned
until it reaches the end of its
travel, and is held in that position
while starting the vehicle, damage
may occur to the hydraulic power
steering system and there may be
loss of power steering assist.
Starting Procedure
1. With your foot off the accelerator pedal, turn the ignition key to
START. When the engine starts,
let go of the key. The idle speed
will go down as your engine gets
warm. Do not race the engine
immediately after starting it.
Operate the engine and
transmission gently to allow the
oil to warm up and lubricate all
moving parts.
When the Low Fuel warning
lamp is on and the FUEL LEVEL
LOW message is displayed in
the Driver Information Center

Black plate (17,1)Chevrolet Express Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
7707481) - 2015 - CRC - 4/30/14
Driving and Operating 9-17
(DIC), the Computer-Controlled
Cranking System is disabled to
prevent possible vehicle
component damage. When this
happens, hold the ignition switch
in the START position to
continue engine cranking.
{Caution
Cranking the engine for long
periods of time, by returning the
ignition to the START position
immediately after cranking has
ended, can overheat and damage
the cranking motor, and drain the
battery. Wait at least 15 seconds
between each try, to let the
cranking motor cool down.
2. If the engine does not start after 5-10 seconds, especially in very
cold weather (below −18°C or
0°F), it could be flooded with too
much gasoline. Try pushing the
accelerator pedal all the way to
the floor and holding it there as
you hold the key in START for up to 15 seconds. Wait at least
15 seconds between each try, to
allow the cranking motor to cool
down. When the engine starts,
let go of the key and accelerator.
If the vehicle starts briefly but
then stops again, do the same
thing. This clears the extra
gasoline from the engine. Do not
race the engine immediately
after starting it. Operate the
engine and transmission gently
until the oil warms up and
lubricates all moving parts.
Fast Idle System
If equipped, this feature is available
only with cruise control. The manual
fast idle switch is operated using the
cruise control buttons on the left
side of the steering wheel.
This system can be used to
increase engine idle speed
whenever the following conditions
are met:
.The parking brake is set.
.The brake pedal is not pressed.
.The vehicle must not be moving
and the accelerator must not be
pressed.
To control the fast idle:
.To enable the Fast Idle System,
press and release the cruise
control on/off button and ensure
that the switch indicator light
is lit.
.Press and release the cruise
control SET- button. Engine
speed will be held at
approximately 1200 rpm.
When the fast idle is active, the
Driver Information Center (DIC) will
display FAST IDLE ON.
One of the following actions will turn
off the fast idle:
.Pressing the brake.
.Selecting the cruise control
cancel button.
.Releasing the parking brake.
.Moving the transmission shift
lever out of P (Park) or
N (Neutral).

Black plate (18,1)Chevrolet Express Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
7707481) - 2015 - CRC - 4/30/14
9-18 Driving and Operating
.Selecting the cruise control on/
off button when it was
previously on.
.Pressing the cruise control SET-
button a second time.
.Pressing the accelerator more
than one-quarter of the
way down.
.Turning the ignition switch to the
LOCK/OFF position.
Engine Heater
If the vehicle has a diesel engine,
see the Duramax diesel supplement
for more information.
The engine coolant heater can
provide easier starting and better
fuel economy during engine
warm-up in cold weather conditions
at or below−18°C (0°F). Vehicles
with an engine coolant heater
should be plugged in at least four
hours before starting. An internal
thermostat in the plug-end of the cord may exist which will prevent
engine coolant heater operation at
temperatures above
−18°C (0°F).
To Use the Engine Coolant
Heater
1. Turn off the engine.
2. Open the hood and unwrap the
electrical cord.
The cord for the engine coolant
heater is located on the driver
side of the engine compartment
and is attached to the hose for
the power steering reservoir.
Check the heater cord for
damage. If it is damaged, do not
use it. See your dealer for a
replacement. Inspect the cord for
damage yearly.
3. Plug it into a normal, grounded 110-volt AC outlet.
{Warning
Improper use of the heater cord
or an extension cord can damage
the cord and may result in
overheating and fire.
.Plug the cord into a
three-prong electrical utility
receptacle that is protected
by a ground fault detection
function. An ungrounded
outlet could cause an electric
shock.
.Use a weatherproof,
heavy-duty, 15 amp-rated
extension cord if needed.
Failure to use the
recommended extension cord
in good operating condition,
or using a damaged heater or
extension cord, could make it
(Continued)

Black plate (19,1)Chevrolet Express Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
7707481) - 2015 - CRC - 4/30/14
Driving and Operating 9-19
Warning (Continued)
overheat and cause a fire,
property damage, electric
shock, and injury.
.Do not operate the vehicle
with the heater cord
permanently attached to the
vehicle. Possible heater cord
and thermostat damage could
occur.
.While in use, do not let the
heater cord touch vehicle
parts or sharp edges. Never
close the hood on the
heater cord.
.Before starting the vehicle,
unplug the cord, reattach the
cover to the plug, and
securely fasten the cord.
Keep the cord away from any
moving parts.4. Before starting the engine, be
sure to unplug and store the
cord as it was before to keep it
away from moving engine parts
and prevent damage.
The length of time the heater should
remain plugged in depends on
several factors. Ask a dealer in the
area where you will be parking the
vehicle for the best advice on this.
Retained Accessory
Power (RAP)
These vehicle accessories can be
used for up to 10 minutes after the
engine is turned off:
.Audio System
.Power Windows (if equipped)
These features will work when the
ignition key is in ON/RUN or ACC/
ACCESSORY. Once the key is
turned from ON/RUN to LOCK/OFF,
power to the radio and power
windows will continue to work
10 minutes or until the driver door is
opened.
Shifting Into Park
1. Hold the brake pedal down, then set the parking brake.
2. Move the shift lever into the P (Park) position by pulling the
shift lever toward you and
moving it up as far as it will go.
3. Turn the ignition key to LOCK/OFF.
4. Remove the key and take it with you. If you can leave the vehicle
with the ignition key in your
hand, the vehicle is in P (Park).
Leaving the Vehicle with the
Engine Running
{Warning
It can be dangerous to leave the
vehicle with the engine running.
It could overheat and catch fire.
(Continued)

Black plate (20,1)Chevrolet Express Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
7707481) - 2015 - CRC - 4/30/14
9-20 Driving and Operating
Warning (Continued)
It is dangerous to get out of the
vehicle if the 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. If you have 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).
SeeShifting Into Park on
page 9-19. If you are towing a
trailer, see Driving Characteristics
and Towing Tips on page 9-44.
If you have to leave the vehicle with
the engine running, be sure the
vehicle is in P (Park) and the
parking brake is firmly set. After the
shift lever is moved into P (Park),
hold the regular brake pedal down. Then, see if you can move the shift
lever away from P (Park) without
first pulling it toward you. If you can,
it means that the shift lever was not
fully locked into P (Park).
Torque Lock
If you are parking on a hill and you
do not shift the transmission into
P (Park) properly, the weight of the
vehicle can put too much force on
the parking pawl in the
transmission. It might be difficult to
pull the shift lever out of P (Park).
This is called torque lock. To
prevent torque lock, set the parking
brake and then shift into P (Park)
properly before you leave the driver
seat. To find out how, see
Shifting
Into Park on page 9-19.
When you are ready to drive, move
the shift lever out of P (Park) before
releasing the parking brake.
If torque lock does occur, you might
need to have another vehicle push
yours a little uphill to take some of
the pressure from the parking pawl in the transmission. Then you
should be able to pull the shift lever
out of P (Park).
Shifting out of Park
The vehicle has an automatic
transmission shift lock control
system. You have to fully apply the
brakes before you can shift from
P (Park) when the ignition is in ON/
RUN or ACC/ACCESSORY. See
Automatic Transmission on
page 9-22.
The shift lock control system is
designed to do the following:
.Prevent the ignition key from
being removed unless the shift
lever is in P (Park).
.Prevent movement of the shift
lever out of P (Park), unless the
ignition is in ON/RUN or ACC/
ACCESSORY and the regular
brake pedal is applied.

Black plate (21,1)Chevrolet Express Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
7707481) - 2015 - CRC - 4/30/14
Driving and Operating 9-21
The shift lock control system is
always functional except in the case
of a dead battery or low voltage
(less than 9 V) battery.
If the vehicle has an uncharged
battery or a battery with low voltage,
try charging or jump starting the
battery. SeeJump Starting on
page 10-74 for more information.
To shift out of P (Park) use the
following:
1. Apply the brake pedal.
2. Turn the ignition to ACC/ ACCESSORY or ON/RUN.
3. Move the shift lever to the desired position.
If you still are unable to shift out of
P (Park):
1. Ease the pressure on the shift lever. 2. While holding down the brake
pedal, push the shift lever all the
way into P (Park).
3. Move the shift lever to the desired position.
If you are still having a problem
shifting, have the vehicle serviced.
Parking over Things
That Burn
{Warning
Things that can burn could touch
hot exhaust parts under the
vehicle and ignite. Do not park
over papers, leaves, dry grass,
or other things that can burn.
Engine Exhaust
{Warning
Engine exhaust contains carbon
monoxide (CO) which cannot be
seen or smelled. Exposure to CO
can cause unconsciousness and
even death.
Exhaust may enter the vehicle if:
.The vehicle idles in areas
with poor ventilation (parking
garages, tunnels, deep snow
that may block underbody
airflow or tail pipes).
.The exhaust smells or
sounds strange or different.
.The exhaust system leaks
due to corrosion or damage.
.The vehicle exhaust system
has been modified, damaged,
or improperly repaired. (Continued)

Black plate (22,1)Chevrolet Express Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
7707481) - 2015 - CRC - 4/30/14
9-22 Driving and Operating
Warning (Continued)
.There are holes or openings
in the vehicle body from
damage or aftermarket
modifications that are not
completely sealed.
If unusual fumes are detected or
if it is suspected that exhaust is
coming into the vehicle:
.Drive it only with the windows
completely down.
.Have the vehicle repaired
immediately.
Never park the vehicle with the
engine running in an enclosed
area such as a garage or a
building that has no fresh air
ventilation.
Running the Vehicle
While Parked
It is better not to park with the
engine running.
If the vehicle is left with the engine
running, follow the proper steps to
be sure the vehicle will not move.
See Shifting Into Park on page 9-19
and Engine Exhaust on page 9-21.
If parking on a hill and pulling a
trailer, see Driving Characteristics
and Towing Tips on page 9-44.
Automatic
Transmission
A shift position indicator is in the
instrument cluster.
There are several different positions
for the shift lever.
See “Range Selection Mode” under
Manual Mode on page 9-26.
P (Park): This position locks the
rear wheels. It is the best position to
use when starting the engine
because the vehicle cannot move
easily. When parked on a hill,
especially when the vehicle has a
heavy load, you might notice an
increase in the effort to shift out of
P (Park). See “Torque Lock” under
Shifting Into Park on page 9-19.

Black plate (23,1)Chevrolet Express Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
7707481) - 2015 - CRC - 4/30/14
Driving and Operating 9-23
{Warning
It is dangerous to get out of the
vehicle if the 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. If you have 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).
SeeShifting Into Park on
page 9-19 andDriving
Characteristics and Towing Tips
on page 9-44.
R (Reverse): Use this gear to
back up.
{Caution
Shifting to R (Reverse) while the
vehicle is moving forward could
damage the transmission. The
repairs would not be covered by
the vehicle warranty. Shift to
R (Reverse) only after the vehicle
is stopped.
To rock the vehicle back and forth to
get out of snow, ice, or sand without
damaging the transmission, see If
the Vehicle Is Stuck on page 9-8.
N (Neutral): In this position, the
engine does not connect with the
wheels. To restart when you are
already moving, use N (Neutral)
only. Also, use N (Neutral) when the
vehicle is being towed.
{Warning
Shifting into a drive gear while the
engine is running at high speed is
dangerous. Unless your foot is
firmly on the brake pedal, the
vehicle could move very rapidly.
You could lose control and hit
people or objects. Do not shift
into a drive gear while the engine
is running at high speed.
{Caution
Shifting out of P (Park) or
N (Neutral) with the engine
running at high speed may
damage the transmission. The
repairs would not be covered by
the vehicle warranty. Be sure the
engine is not running at high
speed when shifting the vehicle.

Black plate (24,1)Chevrolet Express Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
7707481) - 2015 - CRC - 4/30/14
9-24 Driving and Operating
D (Drive):This position is for
normal driving. It provides the best
fuel economy. If you need more
power for passing, and you are:
.Going less than about 55 km/h
(35 mph), push the accelerator
pedal about halfway down.
.Going about 55 km/h (35 mph) or
more, push the accelerator all
the way down.
By doing this, the vehicle shifts
down to the next gear and has
more power.
D (Drive) can be used when towing
a trailer, carrying a heavy load,
or driving on steep hills. You might
want to shift the transmission to a
lower gear selection if the
transmission shifts too often.
Downshifting the transmission in
slippery road conditions could result
in skidding. See “Skidding”under
Loss of Control on page 9-5.
The vehicle has a shift stabilization
feature that adjusts the transmission
shifting to the current driving conditions in order to reduce rapid
upshifts and downshifts. This shift
stabilization feature is designed to
determine, before making an
upshift, if the engine is able to
maintain vehicle speed by analyzing
things such as vehicle speed,
throttle position, and vehicle load.
If the shift stabilization feature
determines that a current vehicle
speed cannot be maintained, the
transmission does not upshift and
instead holds the current gear.
In some cases, this could appear to
be a delayed shift, however the
transmission is operating normally.
The transmission uses adaptive
shift controls. Adaptive shift controls
continually compare key shift
parameters to pre-programmed
ideal shifts stored in the
transmission’s computer. The
transmission constantly makes
adjustments to improve vehicle
performance according to how the
vehicle is being used, such as with
a heavy load or when the
temperature changes. During this
adaptive shift control process,
shifting might feel different as the
transmission determines the best
settings.
The shift quality of a new vehicle
may not be ideal because the
adaptive shift control process may
not have determined the best
settings for a particular shift or
condition. Shift quality will improve
with continued driving.
When temperatures are very cold,
the transmission's gear shifting
could be delayed, providing more
stable shifts until the engine warms
up. Shifts could be more noticeable
with a cold transmission. This
difference in shifting is normal.
M (Manual Mode):
This position
lets drivers select the range of gears
appropriate for current driving
conditions. If the vehicle has this
feature, see “Range Selection
Mode” underManual Mode on
page 9-26.

Black plate (25,1)Chevrolet Express Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
7707481) - 2015 - CRC - 4/30/14
Driving and Operating 9-25
3 (Third):This position is also used
for normal driving. It reduces vehicle
speed more than D (Drive) without
using the brakes. You might choose
3 (Third) instead of D (Drive) when
driving on hilly, winding roads; when
towing a trailer, so there is less
shifting between gears; and when
going down a steep hill. See “Range
Selection Mode” underManual
Mode on page 9-26.
2 (Second): This position reduces
vehicle speed even more than
3 (Third) without using the brakes.
You can use 2 (Second) on hills.
It can help control vehicle speed as
you go down steep mountain roads,
but then you would also want to use
the brakes off and on. See “Range
Selection Mode” underManual
Mode on page 9-26.
If you manually select 2 (Second) in
an automatic transmission, the
transmission will start in
second gear. You can use this
feature for reducing the speed of the rear wheels when trying to start the
vehicle from a stop on slippery road
surfaces.
1 (First):
This position reduces
vehicle speed without using the
brakes. You can use it for major/
severe downgrades where the
vehicle would otherwise accelerate
due to steepness of grade. When
you shift to 1 (First) it provides the
lowest gear appropriate to current
road speed and continues to
downshift as the vehicle slows,
eventually downshifting to 1 (First)
gear. The transmission can be held
in 1 (First) gear using Range
Selection Mode or the shift lever.
See “Range Selection Mode” under
Manual Mode on page 9-26.
{Caution
Spinning the tires or holding the
vehicle in one place on a hill
using only the accelerator pedal
may damage the transmission.
(Continued)
Caution (Continued)
The repair will not be covered by
the vehicle warranty. If you are
stuck, do not spin the tires. When
stopping on a hill, use the brakes
to hold the vehicle in place.
Normal Mode Grade Braking
This mode is enabled when the
vehicle is started, but is not enabled
in Range Selection Mode. It assists
in maintaining desired vehicle
speeds when driving on downhill
grades by using the engine and
transmission to slow the vehicle.
The first time the system activates
for each ignition key cycle, a DIC
message will be displayed. See
Transmission Messages on
page 5-36.