2009 GMC YUKON ECU

Passenger Sensing System
The vehicle has a passenger sensing system for the
right front passenger position. The passenger airbag
status indicator will be visible on the overhead console
when the vehicle is started.
The words ON and OFF, or the symbol for on and off,
will be visible during the system check. If you are using
remote start to start the vehicle from a distance, if
equipped, you may not see the system check. When the
system check is complete, either the word ON or OFF, or
the symbol for on or off, will be visible. SeePassenger
Airbag Status Indicator on page 3-38.The passenger sensing system will turn off the right
front passenger frontal airbag under certain conditions.
The driver airbag and the roof-rail airbags (if equipped)
are not affected by the passenger sensing system.
The passenger sensing system works with sensors that
are part of the right front passenger seat and safety
belt. The sensors are designed to detect the presence
of a properly-seated occupant and determine if the
right front passenger frontal airbag should be enabled
(may inate) or not.
According to accident statistics, children are safer when
properly secured in a rear seat in the correct child
restraint for their weight and size.
We recommend that children be secured in a rear seat,
including: an infant or a child riding in a rear-facing
child restraint; a child riding in a forward-facing child
seat; an older child riding in a booster seat; and children,
who are large enough, using safety belts. United States
Canada
1-90

A label on the sun visor says, “Never put a rear-facing
child seat in the front.” This is because the risk to
the rear-facing child is so great, if the airbag deploys.
{CAUTION:
A child in a rear-facing child restraint can be
seriously injured or killed if the right front
passenger airbag inates. This is because the
back of the rear-facing child restraint would be
very close to the inating airbag. A child in a
forward-facing child restraint can be seriously
injured or killed if the right front passenger airbag
inates and the passenger seat is in a forward
position.
CAUTION: (Continued)
CAUTION: (Continued)
Even if the passenger sensing system has turned
off the right front passenger frontal airbag, no
system is fail-safe. No one can guarantee that an
airbag will not deploy under some unusual
circumstance, even though the airbag is turned off.
Secure rear-facing child restraints in a rear seat,
even if the airbag is off. If you secure a
forward-facing child restraint in the right front seat,
always move the front passenger seat as far back
as it will go. It is better to secure the child restraint
in a rear seat.
1-91

If the On Indicator is Lit for a Child
Restraint
If a child restraint has been installed and the on
indicator is lit:
1. Turn the vehicle off.
2. Remove the child restraint from the vehicle.
3. Remove any additional items from the seat such as
blankets, cushions, seat covers, seat heaters, or
seat massagers.
4. Reinstall the child restraint following the directions
provided by the child restraint manufacturer and
refer toSecuring a Child Restraint in the Right Front
Seat Position on page 1-78.5. If, after reinstalling the child restraint and restarting
the vehicle, the on indicator is still lit, turn the vehicle
off. Then slightly recline the vehicle seatback and
adjust the seat cushion, if adjustable, to make sure
that the vehicle seatback is not pushing the child
restraint into the seat cushion.
Also make sure the child restraint is not trapped
under the vehicle head restraint. If this happens,
adjust the head restraint. SeeHead Restraints
on page 1-2.
6. Restart the vehicle.
The passenger sensing system may or may not
turn off the airbag for a child in a child restraint
depending upon the child’s seating posture
and body build. It is better to secure the child
restraint in a rear seat.
1-93

In addition, your vehicle has a passenger sensing
system for the right front passenger’s position, which
includes sensors that are part of the passenger’s
seat. The passenger sensing system may not
operate properly if the original seat trim is replaced
with non-GM covers, upholstery or trim, or with GM
covers, upholstery or trim designed for a different
vehicle. Any object, such as an aftermarket seat
heater or a comfort enhancing pad or device,
installed under or on top of the seat fabric, could also
interfere with the operation of the passenger sensing
system. This could either prevent proper deployment
of the passenger airbag(s) or prevent the passenger
sensing system from properly turning off the
passenger airbag(s). SeePassenger Sensing
System on page 1-90.
If you have any questions about this, you should
contact Customer Assistance before you modify
your vehicle. The phone numbers and addresses for
Customer Assistance are in Step Two of the
Customer Satisfaction Procedure in this manual.
SeeCustomer Satisfaction Procedure on page 7-2.
If your vehicle has rollover roof-rail airbags, see
Different Size Tires and Wheels on page 5-82
for additional important information.Q:What if I added a snow plow? Will it keep the
airbags from working properly?
A:We have designed our airbag systems to work
properly under a wide range of conditions, including
snow plowing with vehicles that have the optional
Snow Plow Prep Package (RPO VYU). But do
not change or defeat the snow plow’s “tripping
mechanism.” If you do, it can damage your snow
plow and your vehicle, and it may cause an airbag
ination.
Q:Because I have a disability, I have to get my
vehicle modied. How can I nd out whether
this will affect my airbag system?
A:If you have questions, call Customer Assistance.
The phone numbers and addresses for Customer
Assistance are in Step Two of the Customer
Satisfaction Procedure in this manual. See
Customer Satisfaction Procedure on page 7-2.
In addition, your dealer/retailer and the service manual
have information about the location of the airbag sensors,
sensing and diagnostic module and airbag wiring.
1-97

Keys...............................................................2-3
Remote Keyless Entry (RKE) System..................2-4
Remote Keyless Entry (RKE) System
Operation...................................................2-5
Remote Vehicle Start......................................2-7
Doors and Locks............................................2-10
Door Locks..................................................2-10
Power Door Locks........................................2-10
Delayed Locking...........................................2-10
Programmable Automatic Door Locks..............2-11
Rear Door Security Locks..............................2-11
Lockout Protection........................................2-12
Liftgate/Liftglass............................................2-12
Power Liftgate..............................................2-14
Power Assist Steps.......................................2-17
Windows........................................................2-18
Power Windows............................................2-19
Sun Visors...................................................2-20
Theft-Deterrent Systems..................................2-20
Content Theft-Deterrent.................................2-21
PASS-Key
®III+ Electronic Immobilizer.............2-22
PASS-Key®III+ Electronic Immobilizer
Operation.................................................2-23Starting and Operating Your Vehicle................2-24
New Vehicle Break-In....................................2-24
Ignition Positions..........................................2-25
Retained Accessory Power (RAP)...................2-26
Starting the Engine.......................................2-26
Adjustable Throttle and Brake Pedal................2-27
Engine Coolant Heater..................................2-28
Active Fuel Management™.............................2-29
Automatic Transmission Operation...................2-29
Tow/Haul Mode............................................2-35
Four-Wheel Drive..........................................2-37
Parking Brake..............................................2-42
Shifting Into Park..........................................2-44
Shifting Out of Park......................................2-45
Parking Over Things That Burn.......................2-46
Engine Exhaust............................................2-46
Running the Vehicle While Parked..................2-47
Mirrors...........................................................2-48
Manual Rearview Mirror.................................2-48
Automatic Dimming Rearview Mirror................2-48
Outside Manual Mirrors..................................2-49
Outside Towing Mirrors..................................2-49
Outside Power Mirrors...................................2-50
Outside Power Foldaway Mirrors.....................2-50
Section 2 Features and Controls
2-1

Pressing the power lock switch twice or the lock button
on the RKE transmitter twice will override the delayed
locking feature and immediately lock all the doors.
This feature will not operate if the key is in the ignition.
You can program this feature using the Driver
Information Center (DIC). See DELAY DOOR LOCK
underDIC Vehicle Customization (With DIC Buttons) on
page 3-74.
Programmable Automatic Door
Locks
Vehicles with an automatic lock/unlock feature enable
you to program the vehicle’s power door locks. You can
program this feature through the Driver Information
Center (DIC). SeeDIC Vehicle Customization (With DIC
Buttons) on page 3-74for more information on DIC
programming.
Rear Door Security Locks
Your vehicle has rear door security locks. These
prevent passengers from opening the rear doors from
the inside.
The rear door security
locks are located on the
inside edge of each
rear door.
The rear doors must be open to access them. The
label showing lock and unlock positions is located near
the lock.
To set the locks, do the following:
1. Insert the key into the security lock slot and turn it
so the slot is in the horizontal position.
2. Close the door.
2-11

When you want to open a rear door when the security
lock is on, do the following:
1. Unlock the door by lifting the rear door manual lock,
using the power door lock switch, or the Remote
Keyless Entry (RKE) transmitter, if the vehicle
has one.
2. Open the door from the outside.
To cancel the rear door security lock, do the following:
1. Unlock the door and open it from the outside.
2. Insert the key into the security lock slot and turn it
so the slot is in the vertical position.
Lockout Protection
This feature protects you from locking the key in the
vehicle when the key is in the ignition and a front door
is open.
If the driver’s side power door lock switch is pressed
when the driver’s door is open and the key is in the
ignition, all of the doors will lock and then the driver’s
door will unlock.
If the passenger’s side power door lock switch is
pressed when the front passenger’s door is open and
the key is in the ignition, all of the doors will lock
and then the front passenger’s door will unlock.
Liftgate/Liftglass
{CAUTION:
It can be dangerous to drive with the liftglass or
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.
If you must drive with the liftglass or liftgate open, or
if electrical wiring or other cable connections must
pass through the seal between the body and the
liftglass or 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.
SeeClimate Control System on page 3-22or
Dual Automatic Climate Control System on
page 3-25.
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.
SeeEngine Exhaust on page 2-46.
2-12

Content Theft-Deterrent
Your vehicle may have a content theft-deterrent alarm
system.
This is the security light.
To arm the theft-deterrent system:
1. Open the door.
2. Lock the door with the Remote Keyless Entry (RKE)
transmitter or the power door lock switch. The
security light will come on to inform the driver the
system is arming. If a door is open when the doors
are locked, the security light will ash.
If the delayed locking feature is turned on, the
theft-deterrent system will not start the arming
process until the last door is closed and the delay
timer has expired. SeeDelayed Locking on
page 2-10.
3. Close all doors. The security light should go off
after about 30 seconds. The alarm is not armed
until the security light goes off.If a locked door is opened without using the RKE
transmitter, a ten second pre-alarm will occur. The horn
will chirp and the lights will ash. If the key is not
placed in the ignition and turned to START or the door
is not unlocked by pressing the unlock button on the
RKE transmitter during the ten second pre-alarm,
the alarm will go off. Your vehicle’s headlamps will ash
and the horn will sound for about two minutes, then
will turn off to save the battery power.
The theft-deterrent system will not activate if the doors
are locked with the vehicle’s key or the manual door lock.
It activates only if you use the power door lock switch with
the door open or the RKE transmitter. You should also
remember that you can start your vehicle with the correct
ignition key if the alarm has been set off.
To avoid setting off the alarm by accident:
If you do not want to activate the theft-deterrent
system, the vehicle should be locked with the
door key after the doors are closed.
Always unlock the doors with the RKE transmitter.
Unlocking a door any other way will set off the
alarm if it is armed.
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.
2-21