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Notice:If you continue driving your vehicle
after the transmission warning light comes on,
you could damage the transmission. While
this light is on, the transmission cannot
operate in all gears. If you attempt to shift
gears, the vehicle may not continue to move.
Do not attempt to shift gears while the
transmission warning light is on. Instead, drive
directly to an authorized dealer for service. If
you cannot drive to a dealer immediately, have
the vehicle towed.
Range Inhibit Warning Indicator
If your vehicle has an Allison 1000/2200/2300/
2500 series automatic transmission, a lighted bar
under the current gear selected will flash.
If your vehicle has an Allison 3000/3500
series automatic transmission, the current gear
selected on the pushbutton display will flash.
The flashing bar or gear selection indicates that
transmission range shifts may not occur.
For detailed information on shift inhibit limitations,
see the Allison Automatic Transmission
Operator’s Manual in your vehicle for further
information.
Brake System Warning Light
Your vehicle has either hydraulic or air brakes.
Each system has different warning lights.
Hydraulic Brake System
Warning Lights
Vehicles with hydraulic brake systems
have two brake system warning lights on the
instrument panel.
If the brake system
warning light comes on,
it means that the
fluid level in the master
cylinder reservoir is
low or there is another
problem with your
hydraulic brakes.
When it comes on, you will also hear a
warning tone.
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The brake system warning light may come on, and
the warning tone may sound, when you are
turning and braking at the same time. This is
normal. See “Hydraulic Brake Systems” under
Braking on page 210.
This light is located
above the climate
controls in the center of
the instrument panel.
If the service brakes soon warning light comes on,
it means there may be something wrong in the
brake system.
When this light comes on, you will also hear a
warning tone. Have the system repaired
immediately.Both of these lights should come on briefly every
time you start your engine. If they do not come
on then, have them fixed so they will be ready to
warn you if there is a problem. If one or both
of these warning lights stay on after you start the
engine, there could be a brake problem. Have
your brake system inspected right away.
If one or both of these lights come on while you
are driving, pull off the road and stop carefully. You
may notice that the pedal is harder to push, or
the pedal may go closer to the floor. It may take
longer to stop. If this light is still on, have the
vehicle towed for service. SeeTowing Your
Vehicle on page 241. See “Hydraulic Brake
Systems” underBraking on page 210for further
information.
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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.
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Anti-Lock Brake System
Warning Light
This light will come on
briefly when you start
your engine, then
it will turn off. This
is normal.
If the light stays on, or comes on when you are
driving, your vehicle needs service. If the BRAKE
or LOW AIR warning light is not on, you still
have brakes, but you do not have the anti-lock
brake feature. If the BRAKE and/or LOW AIR
warning light is on, you do not have anti-lock
brakes and there is a problem with your regular
brakes. SeeBrake System Warning Light on
page 169andAnti-Lock Brake System (ABS) on
page 212for more information.
The anti-lock brake system warning light should
come on briefly when you turn the ignition
key to ON. If the light does not come on then,
have it fixed so it will be ready to warn you if
there is a problem.
Trailer Anti-Lock Brake System
Warning Light
This light is located
above the climate
controls in the center of
the instrument panel.
If your vehicle is connected to a trailer with
anti-lock brakes, this light should come on briefly,
as a check, when you turn on the ignition.
When this light comes on and stays on, it means
there is something wrong in the trailer anti-lock
brake system. Have the system repaired
immediately.
If an anti-lock brake system equipped trailer is not
connected, this light is not functional.
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Engine Coolant Temperature Gage
This gage shows the engine coolant temperature.
If the gage pointer moves into the red area,
your engine coolant might have overheated and
your engine may be too hot. You should pull off the
road, stop your vehicle and turn off the engine
as soon as possible.
SeeEngine Overheating on page 288. If you have
a Caterpillar
®diesel engine, also see your
Caterpillar®Operation & Maintenance Manual.
Low Coolant Warning Light
You have a low coolant
warning light. If this light
comes on, your system
is low on coolant and the
engine may overheat.
The warning light should come on briefly, as a
check, when you turn on the ignition.
When it comes on, you will also hear a warning
tone at several beats per second for 10 seconds.
SeeEngine Coolant (Gas and DURAMAX
®/Isuzu
Engines) on page 284orEngine Coolant
(Caterpillar
®Diesel Engines) on page 287and
have your vehicle serviced as soon as you can.
This light may also come on if your vehicle is
equipped with the automatic engine shutdown
system and engine shutdown has begun.
SeeEngine Alarm and Automatic Shutdownunder
Starting the Diesel Engine on page 100.
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Wait to Start Indicator
If your vehicle has the DURAMAX®6.6L diesel
engine, it will have glow plugs and an air
intake heater. If your vehicle has the Isuzu 6H
diesel engine, it will have glow plugs and an inlet
heater. If your vehicle has a Caterpillar
®engine,
it will have an inlet heater.
The light in the center of
the instrument panel will
come on when the inlet
heater or glow plugs are
on and the ignition key is
in RUN.
Wait until the indicator light goes off before turning
the ignition key to START.
Malfunction Indicator Lamp
Service Engine Soon Light
If this light comes on or
flashes while you are
driving, two things
may happen.
First, you will not 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 awhile, 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.
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Oil Pressure Gage
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:
Do not keep driving if the oil pressure is
low. If you do, your engine can become so
hot that it catches re. You or others
could be burned. Check your oil as soon
as possible and have your vehicle
serviced.
Notice:Lack of proper engine oil maintenance
may damage the engine. The repairs would
not be covered by your warranty. Always follow
the maintenance schedule in this manual for
changing engine oil.
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Low Oil Level Light
Your vehicle may have
a 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.
Vehicles that have Caterpillar
®diesel engines may
not have a low oil level light. In this case, the light
will neither come on as a check when you start your
engine, nor will it come on to indicate a low oil level.
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. SeeEngine Oil (Caterpillar
®DieselEngine) on page 268orEngine Oil (Gasoline
Engine) on page 268orEngine Oil (DURAMAX
®/
Isuzu Diesel Engine) on page 272for further
information.
Notice:Lack of proper engine oil maintenance
may damage the engine. The repairs would
not be covered by your warranty. Always follow
the maintenance schedule in this manual for
changing engine oil.
Change Engine Oil Light
The change engine oil
light should come on
briefly as a bulb
check when you start
the engine. If the
light does not come on,
have it serviced.
If the change engine oil light comes on and stays
on after you start the engine, have the oil
changed.
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