If Your Diesel Engine Will Not Start
If you have run out of fuel, seeRunning Out of Fuel on
page 5-15.
If you are not out of fuel, and your engine will not start,
do this:
Turn your ignition key to RUN. Immediately after the wait
to start light goes off, turn the ignition key to START.
If the light does not go off, wait a few seconds, then try
starting your engine again. And, see your dealer as
soon as you can for a starting system check.
If the light comes on and then goes off and you know
your batteries are charged, but your engine still will not
start, your vehicle needs service.
If the light does not come on when the engine is cold,
your vehicle needs service.
If your batteries do not have enough charge to start
your engine, seeBattery on page 5-55.
Be sure you have the right oil for your engine, and that
you have changed the oil at the proper times. If you
use the wrong oil, your engine may be harder to start.Be sure you are using the proper fuel for existing
weather conditions. SeeWhat Fuel to Use on page 5-8.
If the engine starts, runs a short time, then stops,
your vehicle needs service.
{CAUTION:
Do not use gasoline or starting aids, such as
ether, in the air intake. They could damage
your engine. There could also be a re, which
could cause serious personal injury.
Engine Alarm and Automatic
Shutdown
Your check gages warning light will come on if the
system senses high engine temperature or low engine
oil pressure. If high engine temperature or low engine oil
pressure is detected, you will also hear a tone alarm
at two beats per second. The alarm and the light
will remain on until the condition is fixed. If the engine
temperature or oil pressure condition worsens, the
tone alarm will go to five beats per second.
2-18
The high idle speed will be temporarily interrupted and
the engine speed will return to normal if any of the
following conditions occur:
•The brake pedal is applied.
•The accelerator pedal is pressed.
•The automatic transmission is shifted out of
PARK (P) or NEUTRAL (N).
•The clutch pedal on the manual transmission is
pressed.
•Vehicle speed is detected.
Once these inputs are removed, the engine idle speed
will slowly ramp back up to high idle after the normal
delay, if the conditions for engine coolant temperature
and air intake temperature are still met.
If this feature is turned off, by doing the brake stomp
procedure described above, and then the engine
is started the exhaust brake/restrictor light will flash for
10 seconds and then it will turn off.
Engine Checks Before Operating
When you have started your engine, let it run for
20 to 30 seconds before you put a load on the engine.
But do not leave the vehicle while the engine is running.
Avoid unnecessary idling of diesel engine equipped
vehicles.
If the engine idles too long, the temperature of the
engine coolant will fall below the normal operating
range. Low engine operating temperature causes
several conditions which affect engine operation and
reduce engine life.
The engine should be permitted to go through a
warm-up period. Operate the vehicle at a minimum of
600 rpm during the warm-up period. During this
period and during operation, the following observations
should be made.
2-22
During this warm-up period, check your warning lights
and gages:
•If oil pressure does not begin to rise within
15 seconds of starting, stop the engine and find the
cause. SeeOil Pressure Gage on page 3-37for
more information.
•If the engine coolant temperature gage needle goes
into the hot area on the gage, stop the engine and
find the cause of the overheating. SeeEngine
Coolant Temperature Gage on page 3-35for
more information.
•If you have air brakes, the dual-needle air pressure
gage should read at least 115 psi (790 kPa) for
both service systems before you try to move
the vehicle. When air pressure is below 60 psi
(420 kPa), the LOW AIR light will come on and you
will hear a tone alarm. SeeBrake System Warning
Light on page 3-31for more information. If the
pressure does not build up or drops during warm-up,
stop the engine and find the cause before you try
to move the vehicle. Recommended air pressure
before driving is 120 psi (830 kPa). SeeAir
Pressure Gage on page 3-44for more information.
•The charging system light should come on when
the ignition key is turned to RUN or START and
should go out when the engine is running above
idle. If the light does not go out or comes back on
during normal engine operation, have the charging
system checked right away. (This light tells you
if the generator is not charging; it does not reflect
the condition of the battery.) SeeCharging System
Light on page 3-30for more information.
•The voltmeter charge indicator gage tells you the
condition of your battery’s charge. The gage
should be in the center area during engine
operation. The red area on the left indicates an
undercharge condition; the red area on the
right indicates an overcharge. If the gage is in
either red area, have the battery and charging
system checked right away. SeeVoltmeter Gage
on page 3-30for more information.
Notice:Do not allow the engine to operate at low
idle for more than ve minutes. This can cause
low engine operating temperatures which can
affect engine operation and reduce engine life.
Engine idle speed should be increased to 1200 rpm
whenever extended idle is required. Once started,
the engine should be placed under load to allow the
engine coolant temperature to reach 150°F (66°C)
before shutting off the engine.
2-23
Transmission Temperature Gage.....................3-39
Exhaust Brake Indicator Light.........................3-40
Differential Lock Indicator Light.......................3-40
Reduced Engine Power Light.........................3-41
Highbeam On Light.......................................3-41
Daytime Running Lamps (DRL) Indicator Light.....3-41
Low Washer Fluid Warning Light.....................3-42
Check Gages Warning Light...........................3-42
Fuel Gage...................................................3-42
Water in Fuel Warning Light...........................3-43
Air Filter Restriction Indicator..........................3-43
Air Pressure Gage........................................3-44
Hourmeter Gage...........................................3-44Audio System(s).............................................3-44
Setting the Time...........................................3-45
AM-FM Radio...............................................3-45
Radio with Cassette......................................3-48
Radio with CD..............................................3-53
Theft-Deterrent Feature (Non-RDS Radios).......3-57
Radio Reception...........................................3-57
Care of the Cassette Tape Player...................3-58
Care of Your CDs.........................................3-59
Care of the CD Player...................................3-59
Fixed Mast Antenna......................................3-59
Chime Level Adjustment................................3-59
Section 3 Instrument Panel
3-2
Rear Heating System
If you have a crew cab
and your vehicle has a
rear heater, the
thumbwheel for this
feature is located on
the headliner.
To increase and decrease the flow of heated air to
the rear floor vents, turn the thumbwheel to the
desired fan speed. To turn the fan off, turn the
thumbwheel down.
Warning Lights, Gages, and
Indicators
This part describes the warning lights and gages that
may be on your vehicle. The pictures will help you
locate them.
Warning lights and gages can signal that something is
wrong before it becomes serious enough to cause
an expensive repair or replacement. Paying attention to
your warning lights and gages could also save you
or others from injury.
Warning lights come on when there may be or is a
problem with one of your vehicle’s functions. As you will
see in the details on the next few pages, some
warning lights come on briefly when you start the
engine just to let you know they’re working. If you are
familiar with this section, you should not be alarmed
when this happens.
Gages can indicate when there may be or is a problem
with one of your vehicle’s functions. Often gages
and warning lights work together to let you know when
there’s a problem with your vehicle.
When one of the warning lights comes on and stays on
when you are driving, or when one of the gages
shows there may be a problem, check the section that
tells you what to do about it. Please follow this
manual’s advice. Waiting to do repairs can be
costly – and even dangerous. So please get to know
your warning lights and gages. They’re a big help.
3-24
Engine Road Speed Governor
This system controls maximum vehicle speed
automatically and reduces engine power until vehicle
speed gets down to maximum governed speed.
The default setting for C4500 and C5500 models up to
19,500 lbs GVWR is 80 to 85 mph (128 to 136 km/h).
Most other models have a default setting of 75 mph
(120 km/h), although some tire sizes and tread patterns
may limit maximum speed to 55 to 65 mph
(86 to 105 km/h). You may have a label on the headliner
of your vehicle with more information on your engine road
speed governor. See your GM dealer for assistance with
programming your engine limited speed.
Safety Belt Reminder Light
When the key is turned to RUN or START, a light will
come on for several seconds to remind people to fasten
their safety belts.
The safety belt light will
also come on and stay on
for several seconds.
Safety Belt Reminder Tone
If your vehicle has this feature, when you turn your key
to RUN or START, a tone will sound for several
seconds to remind people to fasten their safety belts.
Airbag Readiness Light
If your vehicle has airbags, there is an airbag readiness
light on the instrument panel, which shows the airbag
symbol. The system checks the airbag’s electrical
system for malfunctions. The light tells you if there is an
electrical problem. The system check includes the
airbag sensors, the airbag modules, the wiring, the
passenger airbag suppression circuit and the crash
sensing and diagnostic module. For more information on
the airbag system, seeAirbag System on page 1-48.
This light will come on
when you start your
vehicle, and it will flash for
a few seconds. Then the
light should go out. This
means the system is ready.
3-27
Charging System Light
The charging system light
may be located in the
instrument panel cluster, or
with the auxiliary warning
lights in the center of
the instrument panel.
It should come on briefly when you turn on the ignition,
before the engine is running, as a check to show
that it is working.
If it stays on, or comes on while you are driving, have
your vehicle checked right away. You could have a loose
generator drive belt or some other problem.
Driving while this light is on will drain your battery. If you
must drive a short distance with the light on, turn off
your radio and other accessories. Sustained driving with
a generator failure could result in a lack of back-up
braking if the engine quits or the power steering pump
should fail.
Voltmeter Gage
When your engine is
running, the voltmeter
gage shows the charging
system voltage.
Readings in either warning zone indicate a possible
problem in the electrical system.
Readings in the low warning zone may occur when a
large number of electrical accessories are operating in
the vehicle and the engine is left at an idle for an
extended period. This condition is normal since the
charging system may not be able to provide full
power at engine idle. As engine speeds are increased,
this condition should correct itself because higher
engine speeds allow the charging system to create
maximum power.
You can only drive a short time on the battery. Be sure
to shut off the radio, the fan or any unnecessary
accessories and have the system serviced.
3-30
Parking Brake Warning Light
This light will also come on when you set the parking
brake. The light will stay on if your parking brake
does not release fully.
Air Brake System Warning Light
Vehicles with air brake systems have a brake system
warning light on the instrument panel.
The LOW AIR warning light should come on, as a
check, whenever you start the engine. However, it is
designed to come on, and stay on, when brake reservoir
pressure has dropped below 60 psi (410 kPa).When the warning light comes on while you are driving,
you should drive only as far as the nearest point of
safety and then stop the vehicle. Here’s a very important
thing for you to know:
{CAUTION:
If the air brake system warning light comes on
and the warning tone sounds, the vehicle can
stop suddenly and without further warning.
This is because the parking brake will come on
if the pressure falls below 35 to 45 psi (240 to
310 kPa). You or others could be injured. If the
air brake system warning light comes on and
the warning tone sounds, stop as soon as you
can. You will not know how quickly the system
is losing pressure, so be aware that the
parking brake may come on suddenly. United States
Canada
3-33