engine CHEVROLET C/K 2003 Service Manual

2-86 Malfunction Indicator Lamp
(Service Engine Soon Light)
If this light comes on
or flashes while you
are driving, two things
may happen.
First, you won't notice any difference in engine
performance, but your tail pipe emissions may increase.
Second, your engine may not run properly or may stall
without warning. If either of these things happen, drive
or tow your vehicle to your dealer for service.This light should come on when the ignition is on, but
the engine is not running, as a check to show you it is
working. If it does not come on at all, have it repaired.
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.

2-87 Oil Pressure Gage
United States Canada
The engine oil pressure gage, on the lower right portion
of your instrument panel cluster, shows engine oil
pressure in psi (pounds per square inch) or in kPa
(kilopascals). Oil pressure may vary with outside
temperature and oil viscosity, but readings of 30 to
40 psi (205 to 275 kPa) on gasoline engines at operating
temperature and moderate road speeds are normal. If
you have a diesel engine, the normal operating range
should be between 35 and 70 psi (240 to 480 kPa).A reading in the low pressure zone may be caused by a
dangerously low oil level or other problem.
If you have a Caterpillar

diesel engine, also see your
Caterpillar
Operation & Maintenance Manual.
CAUTION:
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.
NOTICE:
Damage to your engine from neglected oil
problems can be costly and is not covered by
your warranty.

2-88 Change Oil Light
The change oil light should
come on briefly as a bulb
check when you start the
engine. If the light doesn't
come on, have it serviced.
If the change oil soon light comes on and stays on after
you start the engine, have the oil changed.
For additional information, see ªEngine Oil, When to
Changeº in the Index. To reset the change oil light, see
ªGM Oil Life System
º in the Index.
Low Oil Level Light
This light should come on
as a check, when you start
your engine. If the light
fails to come on, have it
repaired as soon as possible
so you will be aware when
the oil level is low.
If this light comes on and stays on, it means your engine
is low on oil. You need to check the oil level right away.
See ªChecking Engine Oilº in the Index for further
information.

2-89 Reduced Engine Power Warning Light
If the check engine and
reduced engine power lights
are on, the throttle may be
disabled, and a noticeable
reduction in the vehicle's
performance may occur.
If the reduced engine power light is on, but there is no
reduction in performance, proceed to your destination.
The performance may be reduced the next time the
vehicle is driven. The vehicle may be driven at a
reduced speed while the reduced engine power light is
on, but acceleration and speed may be reduced.
Anytime the check engine light stays on, the vehicle
should be taken to an authorized GM dealer as soon as
possible for service.
Engine Overspeed Warning Light
(If Equipped)
If your vehicle has this
light, it will come on if your
engine is operating at too
many revolutions per
minute (rpm).
It will also come on for a moment as a check when you
start your engine.
If it comes on when you're driving, it means that your
rpm are too great. Reduce your engine speed at once.

2-90 Engine Shutdown Warning Light
(If Equipped)
If your vehicle has the
engine shutdown feature,
this light will come on when
engine shutdown is active.
For more information, see ªEngine Alarm and
Automatic Shutdownº in the Index.
Transmission Temperature Gage
(If Equipped)
If you have an automatic
transmission, this gage is
located above the
switchbank in the center of
the instrument panel.
When your ignition is on, the gage shows the
temperature of the transmission oil. A reading in the
warning zone, the red area beginning at 300
F (150
C),
means you must stop driving and check into the cause.
One possible cause is a low oil level in the transmission.
NOTICE:
If you drive when the transmission temperature
gage is in the warning zone, you can badly
damage the transmission.

2-91 Exhaust Brake Indicator Light
(If Equipped)
If your vehicle is equipped
with an exhaust brake, you
will have this light, located
above the comfort controls
in the center of the
instrument panel.
The exhaust brake indicator light will come on and stay
on whenever the diesel engine exhaust brake or exhaust
restrictor is active. For more information, see ªDiesel
Engine Exhaust Brakeº in the Index.
Diff Lock Indicator Light (If Equipped)
This light located in the
center of the instrument
panel is on when the
inter
-axle differential
lock system is in use.
The light will come on momentarily during starting.
If the light fails to come on, have it repaired as soon
as possible so you will be aware when the lock system
is in use.

2-92 Daytime Running Lamps (DRL)
Indicator Light
This light is located on the
instrument panel cluster. It
goes on whenever the
Daytime Running Lamps
are on.
See ªDaytime Running Lampsº in the Index.
When it begins to get dark, the DRL indicator light is a
reminder to turn on your headlamps.
Low Washer Fluid Warning Light
This light will come on
when your vehicle is low on
windshield washer fluid.
For more information, see ªWindshield Washer Fluidº in
the Index.
Check Gages Indicator Light
This light will come on as
you're starting the engine,
just as a check.
If it ever comes on and stays on while you are driving,
however, it means that either your engine coolant
temperature gage or your engine oil pressure gage may
be showing a reading in the warning zone.
When the check gages light comes on, you will also hear
a warning tone. The tone and the light will stay activated
until the problem is corrected.
This light may also come on if your vehicle is equipped
with the optional automatic engine shutdown system and
engine shutdown has begun. See ªEngine Automatic
Shutdownº in the Index.

2-93 Fuel Gage
Your fuel gage is located on
the right side of your
instrument panel cluster.
When the ignition is on, your fuel gage lets you know
about how much fuel you have left. When the gage first
shows empty, you'll still have a little fuel left, but you
should get more fuel soon.
If your vehicle has dual fuel tanks, the reading on the
gage is the total fuel left in both tanks.
Here are four concerns of some operators. None of these
shows a problem with your fuel gage:

The gage moves a little when you turn a corner or
speed up.
The gage doesn't go back to empty when you turn
off the ignition.

At the gas station, the pump shuts off before the gage
reads full.

It takes a little more or less fuel to fill up than the
gage indicated.
If you have a diesel engine, also see your Caterpillar

Operation & Maintenance Manual.
Water in Fuel Warning Light (If Equipped)
If your vehicle is equipped
with a diesel engine, you
may have this light
This light will come on to warn you that there is water
in the fuel system. For more information on how this
light works, see ªDiesel Fuel Requirements and Fuel
Systemº in the Index.

2-94 Air Pressure Gage (If Equipped)
If your vehicle has air
brakes, the air pressure gage
is located above the
switchbank in the center of
the instrument panel.
This gage shows the air pressure for both your front and
rear brake systems.
If the needle on the gage indicates that the air pressure is
below 60 to 75 psi (415 to 517 kPa), the low air warning
light will come on. An alarm will also sound if this
happens.
The yellow pointer shows the pressure available for the
front system, while the green pointer shows pressure for
the rear. There should be no more than 4 psi (28 kPa)
difference showing between the systems.
Don't drive until both pointers are showing at least
115 psi (793 kPa), so you'll have enough air if you
need to apply your brakes.
Air Filter Restriction Indicator (Option)
This optional gage is
located above the
switchbank in the center
of the instrument panel.
It monitors the engine
air filter.
As the filter gets dirty, the yellow indicator will begin to
rise. When it reaches 25 inches of vacuum on the scale,
the filter should be replaced.
After replacing the filter, reset the gage by pressing in
the yellow reset button at the bottom of the gage.
If you have a diesel engine, also see your Caterpillar


Operation & Maintenance Manual.

3-4
(Bi-Level Air Conditioning): This setting divides
airflow between the floor vents and instrument panel
vents. The air conditioning compressor will cycle
continuously in this setting as long as the outside air
temperature is warm enough to activate the compressor.
(Vent): This setting directs air through the
instrument panel vents.
(Floor): This setting directs air through the
floor vents.
(Defog): This setting divides airflow between the
floor vents and windshield vents.
(Defrost): This setting directs air through the
windshield vents. This setting is used to remove fog or
ice from the windshield.
Air Conditioning (If Equipped)
Before using the air conditioning, open the windows to
clear the vehicle of hot air. This reduces the time it takes
for your vehicle to cool down. Then keep your windows
closed for the air conditioner to work at its best.You can use maximum air conditioning with the
temperature knob in the blue area when it's really hot
outside and you need to cool the inside air quickly.
Maximum air conditioning lets in only a little air from
the outside.
If you first use maximum air conditioning, you can then
use regular air conditioning with the temperature knob
in the blue area, as soon as the vehicle has cooled down,
so outside air will be going through your vehicle.
While in maximum air conditioning, regular air
conditioning, bi
-level air conditioning, defog or defrost
mode, you may notice a slight increase or decrease in
engine speed, due to compressor operation. This is
normal because the system is designed to cycle the
compressor on and off to maintain the desired
temperature.
Heating
On cold days, use floor with the temperature knob in the
red area. Outside air will be brought in, heated and
distributed through the floor vents. The heater works
best if you keep your windows closed while using it.
If you use the optional engine coolant heater before
starting your engine, your heating system will produce
warmer air faster to heat the passenger compartment in
cold weather. See ªEngine Coolant Heaterº in the Index.