service indicator GMC SIERRA 1996 Owners Manual

4HI: This setting engages your front axle to help
drive your vehicle.
Use 4HI when you need extra
traction, such
as on snowy or icy roads, or in most
off-road situations.
4LO: This setting also engages your front axle to give
you extra traction. You may never need 4LO. It sends
the maximum power
to all four wheels. You might
choose 4LO
if you were driving off-road in sand, mud
or deep snow and climbing
or descending steep hills.
Indicator lights
in the switches show you which setting
you are in. The indicator lights will come on briefly
when you turn
on the ignition and one will stay on.
If the lights do not come
on, you should take your
vehicle
in for service. An indicator light will flash
while shifting.
It will remain illuminated when the
shift is completed.
Shifting from 2HI to 4HI
Press and release the 4HI switch. This can be done at
any speed, and the front axle will lock automatically.
Shifting from 4HI to 2HI
Press and release the 2HI switch. This can be done at
any speed, and
the front axle will unlock automatically.
Shifting from 2H1 or 4HI to 4LO
To shift from 2HI or 4HI to 4L0, the vehicle must
be stopped or moving less than
3 mph (4.8 kmh) with
the transmission in NEUTRAL
(N). The preferred
method for shifting
into 4LO is to have your vehicle
moving
1 to 2 mph (1.6 to 3.2 km/h). Press and release
the 4LO switch. You must wait for the 4LO indicator
light to stop flashing and remain illuminated before
shifting
your transmission into gear.
If the 4LO switch
is pressed when your vehicle is in
gear and/or moving, the 4LO indicator light
will flash
for 30 seconds and not complete the shift unless your
vehicle
is moving slower than 3 mph (4.8 km/h) and the
transmission is
in NEUTRAL (N).
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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
You will see this light flash
for a few seconds when you
turn your ignition
to RUN
or START. Then the light
should go out. This means
the system is ready.
Charging System Indicator Light
If the air bag readiness light doesn’t come on when you
start your vehicle, or stays on, or comes on when you
are driving, your air bag system may not work properly.
Have your vehicle serviced right away. This
light should come
on
briefly when you turn on the
ignition, before starting the
engine, as
a check to show
you it is working.
After the engine starts,
the light should go out. If it stays
on or comes on while
you are driving, you may have a
problem with your charging system. It could indicate a
problem with the alternator drive belt,
or some other
charging system problem. Have
it checked right away.
Driving while this light is on could drain your battery.
If
you must drive a short distance with this light on, it
helps to turn off all your accessories, such
as the radio
and air conditioner.
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ANTI -
LOCK
Qnti-Lock Brake System Warning Light
With the anti-lock brake.
system, this light will come
on when
you start your
engine and may stay on
for several seconds.
That’s normal.
If the light stays on, or comes on when you’re driving,
your vehicle needs service.
If the regular brake system
warning light isn’t on,
you still have brakes, but you
don’t have anti-lock brakes.
If the regular brake system
warning light is also on, you don’t have anti-lock brakes
and there’s
a problem with your regular brakes. See
“Brake System Warning Light” earlier
in this part.
The anti-lock brake system warning light should come
on briefly 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.
Engine Coolant Temperature Gage
I This gage shows the engine
~ coolant temperature.
It also provides an indicator of how hard your vehicle is
working. During a majority of the operation, the gage
will read 210°F
(100°C) or less. If you are pulling a
load or going up hills, it is normal for the temperature to
fluctuate and approach the 260°F ( 125 “C) mark. If the
gage reaches the 260°F
(I 25 “C) mark, it indicates that
the cooling system is working beyond its capacity.
In “Problems
on the Road,” this manual shows what to
do. See “Engine Overheating” in the Index.
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Malfunction Indicator Lamp (Service
- ;ine Soon Light) (Gasoline Engine)
Your vehicle is equipped
with a computer which
monitors operation
of the
fuel, ignition and emission SERVICE
ENGINE
SOON
control systems.
This system
is called OBD I1 (On-Board
Diagnostics-Second Generation) and is intended to
assure that emissions are at acceptable levels for the
life of the vehicle, helping to produce a cleaner
environment. (In Canada,
OBD TI is replaced by
Enhanced Diagnostics.) The
SERVICE ENGINE SOON
light comes on to indicate that there is a problem and
service
is required. Malfunctions often will be indicated
by the system before any problem
is apparent, which
may prevent more serious damage to your vehicle. This
system is
also designed to assist your service technician
in correctly diagnosing any malfunction.
I NOTICE:
If you keep driving your vehicle with this light
on, after a while, your emission controls may not
work as well, your fuel economy may not be as
good and your engine may not run as smoothly.
This could lead
to costly repairs that may not be
covered by your warranty.
This light should come on, as a check to show you it is
working, when the ignition is
on and the engine is not
running.
If the light doesn’t come on, have it repaired.
This light will also come
on during a malfunction in one
of two ways:
0 Light Flashing -- A misfire condition has been
detected.
A misfire increases vehicle emissions and
may damage
the emission control system on your
vehicle. Dealer or qualified service center diagnosis
and service
is required.
0 Light On Steady -- An emission control system
malfunction has been detected on your vehicle.
Dealer or qualified service center diagnosis and
service may be required.
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/A CAUTION: l!,L- .
Don’t keep driving if the oil pressure is low. If
you do, your engine can become so hot that it
catches fire.
You or others could be burned.
Check
your oil as soon as possible and have your
vehicle serviced.
I NOTICE:
Damage to your engine from neglected oil
problems can be costly and
is not covered by your
warranty.
Shift Light
SHIFT
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.
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Daytime Running Lamps Indicator Light Check Gages Light
This light goes on whenever
the DRL are on.
CHECK
GAGES
This light will come on
briefly when you are
starting
the engine.
When
it begins to get dark, the DRL indicator light is a
reminder to turn
on your headlamps.
If the light comes on and stays on w.hile you are driving,
it could indicate a problem with your vehicle. It could be
a problem with your oil pressure, coolant temperature,
or some other problem. Check your various gages to see
if they are in the warning zones. If they are, have your
vehicle serviced right away.
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If your vehicle is certified to meet California Emission
Standards (indicated on the underhood tune-up label),
it
is designed to operate on fuels that meet California
specifications.
If such fuels are not available in states
adopting California emissions standards,
your vehicle
will operate satisfactorily
on fuels meeting federal
specifications, but emission control system performance
may be affected. The malfunction indicator lamp on
your instrument panel may
turn on and/or your vehicle
may fail a smog-check test.
If this occurs, return to your
authorized GM dealer for diagnosis
to determine the
cause
of failure. In the event it is determined that the
cause
of the condition is the type of fuels used, repairs
may not be covered by
your warranty.
In Canada. some gasolines contain an octane-enhancing
additive called
MMT. If you use such fuels, your
emission control system performance may deteriorate
and the tnalfunction indicator lamp
on your instrument
panel may turn on. If this happens, return to your
authorized
CM dealer for service.
To provide cleaner air, all gasolines are now required to
contain additives that will help prevent deposits from
forming
in your engine and fuel system, allowing your
emission control system
to function properly. Therefore,
you should not have to add anything to the fuel. In
addition, gasolines containing oxygenates, such as ethers
and ethanol, and reformulated gasolines may be
available
in your area to help clean the air. General
Motors recommends that
you use these gasolines if they
comply with the specifications described earlier.
NOTICE:
Your vehicle was not designed for fuel that
contains methanol. Don’t use it.
It can corrode
metal parts
in your fuel system and also damage
plastic and rubber parts. That damage wouldn’t
be covered under your warranty.
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The air cleaner assembly
has an indicator that lets
you know when the air filter
is dirty and needs to be
serviced.
The indicator is
located
in the air intake tube
between the air cleaner and
the engine.
See “Owner Checks and Services”
in the Index on when
to check the indicator.
If the area inside the clear section of the indicator is
green, no air filter service is required. When the area
inside the indicator is orange and
CHANGE AIR
FILTER appears, the filter should be replaced.
To remove the air filter, unhook the retaining clips and
remove the cover. Lift the filter and the connected duct
out of the air cleaner housing. Hold the duct and remove
the filter by both pulling and twisting the
filter away
fram the duct. Care should be taken
to dislodge as little
dirt as possible.
Clean the filter sealing surface of the duct and the
filter housing.
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Install the new filter by pushing it all the way to the stop
on the duct.
Install
the duct and the filter into the air cleaner housing.
Make sure that the duct fits properly into the housing.
Install
the cover and fasten the two retaining clips.
After the air filter
is properly serviced, the indicator
should
be reset. Push the button on top of the indicator
to reset it to the green (clean) filter zone. Refer
to the
Maintenance Schedule to determine when to
replace the air filter.
See “Scheduled Maintenance Services”
in the Index.
I
Operating the engine with the air cleaner off can
cause you
or others to be burned. The air cleaner
not only cleans the air, it stops flame
if the engine
backfires.
If it isn’t there, and the engine
backfires,
you could be burned. Don’t drive with
it
off, and be careful working on the engine with
the
air cleaner off.
I NOTICE:
If the air cleaner is off, a backfire can cause a
damaging engine fire. And, dirt can easily get
into your engine, which
will damage it. Always
have the air cleaner
in place when you’re driving.
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NOTICE:
0
0
Using the wrong fluid can badly damage
brake system parts. For example,.just a few
drops of mineral-based oil, such
as engine
oil,
in your brake system can damage brake
system parts
so badly that they’ll have to be
replaced. Don’t let someone put in the
wrong kind of fluid.
If you spill brake fluid on your vehicle’s
painted surfaces, the paint finish can be
damaged. Be careful not to spill brake
fluid on your vehicle.
If you do, wash it
off immediately. See &‘Appearance Care”
in
the Index.
Brake Wear
If you have a C 3500 HD model, it has four-wheel
disc brakes.
Disc brake pads have built-in wear indicators that
make a high-pitched warning sound when the brake
pads are worn and
new pads are needed. The sound
may come and
go or be heard all the time your vehicle
is moving (except when you are pushing on the brake
pedal firmly).
A’ CAUTION:
I
The brake wear warning sound means that
sooner or later your brakes won’t work well.
That could lead to an accident. When you hear
the brake wear warning sound, have your vehicle serviced.
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