1998 GMC SIERRA ECU

Synchronization
Synchronization may be necessary d~te to the security
method used by this system. The transmitter does not
send the
same signal twice to the receiver. The receiver
will not respond to a signal it has been sent previously.
This prevents anyone from recording and playing back
the signal
from the transmitter.
To resynchronize your transmitter, stand close to your
vehicle and simultaneously press and hold the
LOCK
and UNLOCK buttons on the transmitter for at least
five seconds. The door locks should cycle to confirm
synchronization.
If the locks do not cycle. see your
dealer for service.
Theft
Vehicle theft is big business, especially in scme cities.
Although your vehicle has
a number of theft-deterrent
features, we know that nothing we put on
it can make it
impossible to steal. However. there are ways you can help.
Key in the Ignition
If you leave your vehicle with the keys inside, it's an
easy target forjoy riders
01- professional thieves -- so
don't do it.
When you park your vehicle and open the driver's door,
you'll hear
a tone reminding you to remove your key
from the ignition and take
it with you. Always do this.
Ycx~r steering wheel will be locked, and so will your
ignition.
If you have an automatic transmission, taking
your key
out also locks your transmission. And
remember
to lock the doors.
Parking at Night
Park in a lighted spot, close all windows and lock your
vehicle. Remember
to keep your valuables out of sight.
Put them in a storage area, or take them with you.
Parking Lots
If you park in a lot where someone will be watching
your vehicle, it's best to lock
it up and take your keys.
But what if you have to leave your ignition key? What if
you have to leave something valuable in your vehicle'?
Put your valuables in a storage area, like your
glove box.
Lock all the doors except the driver's.
2-9
ProCarManuals.com

Passlock@ New Vehicle “Break-In”
Your vehicle is equipped with the Passlock
theft-deterrent system.
Passlock is a passive theft-deterrent system. The
system
is armed once the key is removed from the ignition.
Passlock enables fuel if the ignition lock cylinder
is
turned with a valid key. If a correct key is not used, f~lel
is disabled.
During normal operation, the
SECURITY light will go
off after the engine is started.
If the engine stalls and the SECURITY light flashes.
wait
until the light stops flashing before trying to restart
the engine. Remember to release the key from the
START position as soon as the engine starts.
If you are driving and the SECURITY light comes on, you
will be able to restart the engine
if you turn the engine off.
However, your Passlock system is not working properly
and must be serviced by your dealer. Your vehicle is not
protected by Passlock at this time,
You may also want to
check the fuse (see “Fuses
and Circuit Breakers” in the
Index), See your dealer for service.
If the SECURITY light comes on while the engine is
running, a problem has been detected and the system
may need service. See your dealer for service.
In an emergency, call the Roadside Assistance Center.
NOTICE:
Your vehicle doesn’t need an elaborate
“break-in.” But it will perform better in the long
run if you follow these guidelines:
0
0
0
0
Keep your speed at 55 mph (88 kmh) or
less for the first
500 miles (805 km).
Don’t drive at any one speed
-- fast or
slaw
-- for the first 500 miles (805 km).
Don’t make full-throttle starts.
Avoid making hard stops for the first
200 miles (322 km) or so. During this time
your new brake linings aren’t 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.
Don’t tow
a trailer during break-in.
See “Towing
a Trailer” in the Index for
more information.
ProCarManuals.com

Instrument Panel Cluster
CHECK
GAGES SECURITY
MPH
lolololo1 TRIP loo 0 0 oolol
LOCK ANTI -
I APPLY BRAKE TO SHIFT FROM PARK I
United States version shown, Canada similar
Your instrument cluster is designed to let you know at a glance how your vehicle is running. You'll know how fast you're
going, about
how much fuel you have and many other things you'll need to know to drive safely and economically.
2-62
ProCarManuals.com

Air Bag Readiness Light
There is an air bag readiness light on the instrument panel,
which shows AIR BAG. The system checks
the air bag’s
electrical system for malfunctions. The light tells
you if
there is an electrical problem. The system check includes
the air bag sensors, the air bag module, the wiring and the
diagnostic module. For more information
on the air bag
system, see “Air Bag”
in the Index,
~
AIR
BAG
This light will come on
when you start your engine,
and
it will flash for a few
seconds. Then the light
should go out. This means
the system is ready.
If the air bag readiness light stays on after you start the
engine or comes on when
you are driving, your air bag
system may not work properly. Have your vehicle
serviced right away.
The air bag readiness light should flash for a few
seconds when
you turn the ignition key to RUN. If the
light doesn’t come
on then, have it fixed so it will be
ready to warn you
if there is a problem.
AIR BAG OFF Light (Except Crew Cab)
When you turn the right front passenger’s air bag off, this
light will come
on and stay on to remind you that the air
bag has been turned off. This light will go off when you
turn the air bag back on again. See “Securing a Child
Restraint in the Right Front Seat Position”
in the Index for
more on this, including important safety information.
-
2-65
ProCarManuals.com

If the right front passenger’s air bag is turned
off, an adult or
a child who is no longer an infant
sitting in the right front passenger’s position
won’t have the extra protection of an air bag. In
a crash, the air bag wouldn’t be able to inflate
and help protect the person sitting there. Make
sure the air bag is turned on unless you are using
a rear-facing child restraint in the right front
seat position.
A
A CAUTION:
If the air bag readiness light ever comes on when
you have turned off the air bag, it means that
something may be wrong with the air bag system.
The right front passenger’s air bag could inflate
even though the switch is off.
If this ever
happens, don’t secure a rear-facing child
restraint in your vehicle until you have your
vehicle serviced.
Charging System Indicator Light
7-1 This light should come on
I-+I
brieflywhen you turn on the
ignition, before starting the
engine,
as a check to show
you it is working.
2-66
ProCarManuals.com

Security Light
SECURITY
This light will come on
briefly when you turn the
key to
START.
The light will stay on until the engme starts. If the light
flashes, the Passlock@ System has entered a tamper
mode. If the vehicle fails
to start, see “Passlock” in
the Index.
If the light comes on continuously while driving and
stays
on, there may be a problem with the Passlock
System. Your vehicle will
not be protected by Passlock,
and you should see your
GM dealer.
Up Shift Light (If Equipped)
This light is used on
some models with
manual transmissions.
The
SHIFT indicator light will help you get the best fuel
economy. See ‘(Shift Light” or ;’Shift Speeds”
in this
section for more information.
2-73
ProCarManuals.com

Remote Compact Disc Player (If Equipped)
If you have this option, YOU can play one compact disc
(CD) at
a time.
To load a CD into the player, hold the disc with the label
side up and insert it carefully into the player
(approximately halfway). The disc will automatically be
pulled into the player. If the radio is
off and the ignition
is
on when a CD is inserted, the radio will turn on and
begin playing the CD. It is possible to load and unload
CDs with the ignition off.
To load a disc with the
ignition off, press the EJECT button
on the remote
player and then insert the disc. To remove the disc, press
the
EJECT button and remove the disc from the player.
A disc that has been ejected but is still sitting in the
remote CD player will be pulled back into the player
after approximately
30 seconds. This protects the disc
and player from damage. The disc will not start playing.
3-20
To remove the disc, press the EJECT button and remove
the disc from the player.
All of
the compact disc functions are controlled by the
radio buttons except for EJECT. When a disc is in the
player, a CD symbol will appear on the display. When a
disc is playing, the letters CD will appear
next to the CD
symbol
in the bottom left corner. The track number will
also be displayed.
If the disc comes back out and ERR appears on the
display, it could be that:
0 The disc is upside down.
0 It is dirty, scratched or wet.
There’s too much moisture in the air. (Wait about an
hour and try again.)
0 You are driving on a very rough road.
Please contact your dealership if any error recurs or
cannot be corrected.
PREV (1): Press this button to go back to the start of the
current track
if more than eight seconds have played. Press
PREV again to
go to the previous track on the disc.
NEXT (3): Press this button to advance to the next track
on the disc.
ProCarManuals.com

Activating the Theft-Deterrent Feature
The instructions which follow explain how to enter your
secret code to activate the THEFTLOCK system.
It is
recommended that you read through all nine steps
before starting the procedure.
NOTE:
If you allow more than 15 seconds to elapse
between any steps, the radio autonlatically reverts to
time and
you must start the procedure over at Step 4.
1. Write down any three or four-digit number from
000 to 1999 and keep it in a safe place separate from
the vehicle.
2. Turn the ignition to ACCESSORY or RUN.
3. Turn the radio off.
4. Press the 1 and 4 buttons together. Hold them down
until --- shows on the display. Next you will use the
secret code number which you have written down.
5. Press MN and 000 will appear on the display.
6. Press MN again to make the last two digits agree
with your code.
7. Press HR to make the first one or two digits agree
with your code.
8.
9.
Press AM-FM after you have confirmed that the
code matches the secret code you have written down.
The display
will show REP to let you know that you
need to repeat Steps
5 through 7 to confirm your
secret code.
Press AM-FM and
this time the display will show
SEC to let you know that your radio
is secure. The
indicator
by the volume control will begin flashing
when the ignition is turned off.
Unlocking the Theft-Deterrent Feature After a
Power Loss
Enter your secret code as follows; pause no more than
15 seconds between steps:
1. LOC appears when the ignition is on.
2. Press MN and 000 will appear on the display.
3. Press MN again to make the last two digits agree
with your code.
4. Press HR to make the first one or two digits agree
with your code.
5. Press AM-FM after you have confirmed that the
code matches the secret code you have written down.
The display
will show SEC, indicating the radio is
now operable and secure.
3-22
ProCarManuals.com