2008 CADILLAC CTS ECU

In addition, the vehicle has a passenger sensing
system for the right front passenger 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 1-65.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.
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.
1-71

Keys...............................................................2-4
Remote Keyless Entry (RKE) System................2-6
Remote Keyless Entry (RKE) System
Operation...................................................2-7
Keyless Access System...................................2-9
Keyless Access System Operation..................2-10
Remote Vehicle Start....................................2-16
Doors and Locks............................................2-18
Door Locks..................................................2-18
Central Door Unlocking System......................2-19
Power Door Locks........................................2-19
Delayed Locking...........................................2-19
Programmable Automatic Door Locks..............2-20
Rear Door Security Locks..............................2-20
Lockout Protection........................................2-21
Trunk..........................................................2-21
Windows........................................................2-24
Power Windows............................................2-25
Sun Visors...................................................2-27
Theft-Deterrent Systems..................................2-28
Theft-Deterrent System..................................2-28
Immobilizer..................................................2-29
Immobilizer Operation (Key Access)................2-30
Immobilizer Operation (Keyless Access)...........2-31Starting and Operating Your Vehicle................2-32
New Vehicle Break-In....................................2-32
Ignition Positions (Key Access).......................2-32
Ignition Positions (Keyless Access)..................2-34
Retained Accessory Power (RAP)...................2-35
Starting the Engine.......................................2-35
Engine Coolant Heater..................................2-37
Automatic Transmission Operation...................2-38
Manual Transmission Operation......................2-42
Parking Brake..............................................2-44
Shifting Into Park (Automatic Transmission)
......2-45
Shifting Out of Park......................................2-47
Parking the Vehicle (Manual Transmission).......2-47
Parking Over Things That Burn.......................2-48
Engine Exhaust............................................2-48
Running the Vehicle While Parked..................2-49
Mirrors...........................................................2-50
Automatic Dimming Rearview Mirror
with OnStar
®............................................2-50
Outside Power Mirrors...................................2-50
Park Tilt Mirrors............................................2-51
Outside Convex Mirror...................................2-51
Outside Heated Mirrors..................................2-51
Section 2 Features and Controls
2-1

Programmable Automatic Door
Locks
If your vehicle has an automatic transmission, the
vehicle is programmed so that the doors will lock
automatically when all doors are closed, the ignition
is on, and the shift lever is moved out of PARK (P).
The doors will automatically unlock when you stop the
vehicle and move the shift lever back into PARK (P).
If your vehicle has a manual transmission, the vehicle is
programmed so that the doors will lock automatically after
the vehicle speed reaches 5 mph (8 km). The doors will
automatically unlock when the ignition is turned off and
the key is removed from the ignition.
If someone needs to exit the vehicle once the doors
are locked, have that person use the manual lever
or power door lock switch. When the door is closed
again, it will not lock automatically. Use the manual
lever or the power door lock switch to lock the door.
The power door locks can be programmed through
prompts displayed on the Driver Information
Center (DIC). These prompts allow you to choose
various lock and unlock settings. For more information
on programming, seeDIC Vehicle Customization on
page 3-69.
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.Lock Label shown
2-20

When you want to open a rear door when the security
lock is on, do the following:
1. Unlock the door using the Remote Keyless Entry
(RKE) or Keyless Access System transmitter, if
the vehicle has one, the power door lock switch,
or the rear door manual lock.
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
If the power door lock switch is pressed when the key
is in the ignition and a door is open, all the doors will lock
and only the driver’s door will unlock. If you close the
doors, they can be locked by using the Remote Keyless
Entry (RKE) transmitter. Be sure to remove the key from
the ignition when locking your vehicle.
This feature can be overridden by pressing the lock
button on the RKE transmitter or by pressing the power
lock switch a second time.
On vehicles with a Keyless Access System, the system
can be programmed to alert you when all the doors
are closed and a transmitter has been left inside of the
vehicle. SeeDIC Vehicle Customization on page 3-69
for more information.
Trunk
{CAUTION:
It can be dangerous to drive with the trunk lid
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 trunk
lid open or if electrical wiring or other cable
connections must pass through the seal
between the body and the trunk lid:
Make sure all other windows are shut.
Turn the fan on your heating or cooling
system to its highest speed and select the
control setting that will force outside air
into your vehicle. See Climate Control
System.
If you have air outlets on or under the
instrument panel, open them all the way.
SeeEngine Exhaust on page 2-48.
2-21

Close the trunk by pulling on the handle. Do not use the
handle as a tie-down.
Rear-Seat Pass Through
If your vehicle has the rear seat-pass through door,
you can access the trunk without opening the trunk lid.
This is especially useful when transporting long items.
To open the door, pull down the rear seat armrest.
Then pull the lever all the way down to release the door.
To close the door, push it up and back into place.
Then try to open the door without pulling up on the
lever to make sure it is locked into place.
Emergency Trunk Release Handle
Notice:Do not use the emergency trunk release
handle as a tie-down or anchor point when securing
items in the trunk as it could damage the handle.
The emergency trunk release handle is only
intended to aid a person trapped in a latched trunk,
enabling them to open the trunk from the inside.
There is a glow-in-the-dark emergency trunk release
handle located on the back wall of the trunk. This handle
will glow following exposure to light. Pull the release
handle toward the front of the vehicle to open the trunk
from the inside.
2-23

Theft-Deterrent Systems
Vehicle theft is big business, especially in some cities.
This vehicle has theft-deterrent features, however,
they do not make it impossible to steal.
Theft-Deterrent System
If your vehicle has this
feature, the security light is
located on the instrument
panel cluster.
To activate the theft-deterrent system:
1. Open the door.
2. Lock the door with the transmitter. The security light
should come on and stay on.
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 or trunk is opened without using the
key in the driver’s door key cylinder or the 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 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
30 seconds, 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 the power door lock switch
is used while the door is open or with the 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:
Lock the vehicle with the door key after the doors
are closed.
Always unlock a door with the transmitter. Unlocking
a door any other way will set off the alarm.
If you set off the alarm by accident, turn off the alarm by
pressing the unlock button on the transmitter. The alarm
will not stop if you try to unlock a door any other way.
2-28

Testing the Alarm
The alarm can be tested by following these steps:
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
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 5-123
Fuses and Circuit Breakers.
If the alarm does not sound or the headlamps do
not ash, the vehicle should be serviced by your
dealer/retailer.
Immobilizer
This device complies with Part 15 of the FCC Rules.
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.
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.
2-29

Immobilizer Operation (Key Access)
Your vehicle has a passive theft-deterrent system.
The system is automatically armed when the key
is removed from the ignition.
The theft-deterrent system is disarmed when the key is
turned to ON/RUN.
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.
The key uses a transponder that matches an immobilizer
control unit in your vehicle and automatically disarms
the system. Only the correct key will start the vehicle.
If the key is ever damaged, you may not be able to start
your vehicle.
When trying to start the vehicle, if the engine does not
start and the security light comes on, 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 5-123. 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
theft-deterrent system and have a new key made.It is possible for the theft-deterrent system decoder to
learn the transponder value of a new or replacement
key. Up to 10 keys can be programmed for the vehicle.
The following procedure is for programming additional
keys only.
To program a new key do the following:
1. Verify that the new key has
1stamped on it.
2. Insert the current driver’s 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 key to be programmed and turn it to
ON/RUN within ve seconds of the ignition being
turned to LOCK/OFF in Step 3.
5. The security light will turn off once the key has
been programmed. It may not be apparent that
the security light went on due to how quickly the
key is programmed.
6. Repeat the Steps 1 through 4 if additional keys are
to be programmed.
In an emergency, contact Cadillac Roadside Service.
SeeRoadside Service on page 7-7.
Do not leave the key or device that disarms or
deactivates the theft deterrent system in the vehicle.
2-30