
Low Coolant Warning Light
Your vehicle has a low
coolant warning light.
If this light comes on, the
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 for
10 seconds. SeeEngine Coolant (Caterpillar Diesel
Engines) on page 5-47and have your vehicle serviced
as soon as you can.
This light may also come on if your vehicle has the
automatic engine shutdown system and engine
shutdown has begun. SeeEngine Alarm and Automatic
Shutdown on page 2-18for more information.
Wait to Start Light
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 ON/RUN.
Wait until the indicator light goes off before turning the
ignition key to START.
3-35

Malfunction Indicator Lamp
Check Engine Light
A computer system called OBD II (On-Board
Diagnostics-Second Generation) monitors operation
of the fuel, ignition, and emission control systems.
It makes sure that emissions are at acceptable levels
for the life of the vehicle, helping to produce a cleaner
environment.
If this light comes on while
you are driving, two things
can happen.
First, you will not notice any difference in engine
performance, but the tail pipe emissions might increase.
Second, the engine might not run properly or could
stall without warning. If either of these things happen,
see your dealer/retailer for service.This light should come on when the ignition is on, but
the engine is not running, as a check to show it is
working. If it does not come on at all, have it repaired.
Notice:If the vehicle is continually driven with
this light on, after a while, the emission controls
might not work as well, the vehicle’s fuel economy
might not be as good, and the engine might not
run as smoothly. This could lead to costly repairs
that might not be covered by the vehicle warranty.
Notice:Modifications made to the engine,
transmission, exhaust, intake, or fuel system of the
vehicle or the replacement of the original tires
with other than those of the same Tire Performance
Criteria (TPC) can affect the vehicle’s emission
controls and can cause this light to come on.
Modifications to these systems could lead to costly
repairs not covered by the vehicle warranty. This
could also result in a failure to pass a required
Emission Inspection/Maintenance test. See
Accessories and Modifications on page 5-3.
If the check engine light comes on and stays on, while
the engine is running this indicates that there is an
OBDII problem and service is required.
3-36

Engine Overspeed Warning Light
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, reduce your engine
speed immediately.
Engine Shutdown Warning Light
If your vehicle has the
engine shutdown feature,
this light will come on
when engine shutdown is
active.
SeeEngine Alarm and Automatic Shutdown on
page 2-18for more information.
Transmission Temperature Gage
If you have an automatic
transmission and this gage,
it 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 your vehicle with the
transmission temperature gage above normal
operating range, you can damage the transmission.
This could lead to costly repairs that would not
be covered by your warranty. Do not drive your
vehicle while the transmission temperature gage
reading is above normal. See your dealer for service.
3-40

Low Washer Fluid Warning Light
This light is located above
the climate controls in the
center of the instrument
panel.
This light will come on when your vehicle is low on
windshield washer fluid.
For more information, seeWindshield Washer Fluid on
page 5-50.
Power Take-Off Light (PTO)
For vehicles with Power
Take-Off (PTO), this light
is located in the center
of the instrument panel.
This light will come on when the PTO switch is in the
ON/RUN position. SeePower Take-Off (PTO) on
page 2-30for more information.
Check Gages Warning Light
This light will come on
briefly when the engine is
started.
If this light comes on and stays on while you are driving.
It means that either the engine coolant temperature
gage or the 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 has
automatic engine shutdown system and engine
shutdown has begun. SeeEngine Alarm and Automatic
Shutdown on page 2-18.
3-43

Water in Fuel Warning Light
This light is located above
the climate controls in the
center of the instrument
panel.
If your vehicle has the 6.6L DURAMAX
®or a
Caterpillar®diesel engine, this light will come on to
warn you that there is water in the fuel system.
For more information on how this light works, seeWater
in Fuel on page 5-11.
Change Fuel Filter Warning Light
For vehicles with this light,
it is located in the center of
the instrument panel.
If your vehicle has the DURAMAX
®6.6L engine, this
light will come on when the fuel filter needs to be
changed. If your vehicle has the Isuzu 6H 7.8L L6 diesel
engine, this light will come on when water is detected
in the fuel system and when the fuel filter needs to
be changed. SeeFuel Filter Replacement on page 5-18
andWater in Fuel on page 5-11for more information.
3-45

Diesel Particulate Filter Warning
Light
Your vehicle may have two
Diesel Particulate Filter
(DPF) Warning lights.
These lights will come on briefly when the ignition is
turned to ON/RUN. One of these lights will come on
green during DPF regeneration. If the other light comes
on yellow, perform a manual regeneration or drive the
vehicle for automatic regeneration. If the light changes
from yellow to red, the DPF requires an immediate
regeneration. If the DPF is not regenerated, the service
engine soon light will come on and engine power will be
reduced.
SeeDiesel Particulate Filter on page 2-46andReduced
Engine Power Light on page 3-42for more information.
Air Filter Restriction Indicator
If your vehicle has this
feature, the 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 the red/orange change area,
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 Caterpillar
®diesel engine, also see your
Caterpillar®Operation & Maintenance Manual.
3-46

Air Pressure Gage
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 bottom yellow pointer shows the pressure available
for the front secondary system, while the top white
pointer shows pressure for the rear primary system.
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
120 psi (827 kPa), so you’ll have enough air if you need
to apply your brakes.
Hourmeter Gage
To access the engine hourmeter gage, press the trip
odometer button three times.
The instrument panel cluster displays the accumulated
engine run time hours using the reconfigurable odometer
display. The engine run time hours displays only
when the ignition is in the LOCK or ACC/ACCESSORY
position and the trip reset button is pressed for about
four seconds. The value of the accumulated hours does
not change when the battery is disconnected.
The hourmeter resets to 0.0 when 10,000 hours
are accumulated. The instrument panel cluster begins
to reaccumulate the engine run time hours from
0.0 hours.
3-47

Braking
SeeBrake System Warning Light on page 3-31.
Braking action involves perception time and reaction
time. Deciding to push the brake pedal is perception
time. Actually doing it is reaction time.
Average reaction time is about three-fourths of a
second. But that is only an average. It might be less
with one driver and as long as two or three seconds or
more with another. Age, physical condition, alertness,
coordination and eyesight all play a part. So do alcohol,
drugs and frustration. But even in three-fourths of a
second, a vehicle moving at 60 mph (100 km/h) travels
66 feet (20 m). That could be a lot of distance in an
emergency, so keeping enough space between
the vehicle and others is important.
And, of course, actual stopping distances vary greatly
with the surface of the road, whether it is pavement
or gravel; the condition of the road, whether it is wet, dry
or icy; tire tread; the condition of the brakes; the
weight of the vehicle; the weight of the load; and the
amount of brake force applied.
Avoid needless heavy braking. Some people drive
in spurts — heavy acceleration followed by heavy
braking — rather than keeping pace with traffic. This is
a mistake. The brakes might not have time to cool
between hard stops. The brakes will wear out much
faster with a lot of heavy braking. Keeping pace with thetraffic and allowing realistic following distances
eliminates a lot of unnecessary braking. That means
better braking and longer brake life.
If the engine ever stops while the vehicle is being driven,
brake normally but do not pump the brakes. If the brakes
are pumped, the pedal could get harder to push down.
If the engine stops, there will still be some power brake
assist but it will be used when the brake is applied. Once
the power assist is used up, it can take longer to stop and
the brake pedal will be harder to push.
Hydraulic Brake Systems
If the engine stops running, or if the primary brake system
stops working, your vehicle has a reserve power assist
system to help you slow down. Just slowly and steadily
apply the brake pedal until you can safely get off the road.
The pedal will seem harder to push down. Do not pump
the pedal; the system will not work well that way.
You might find that the steering wheel seems hard to
turn when you are turning and braking at the same time.
Also, the primary brake warning light might come on
and the warning tone might sound. This is normal
because the main hydraulic brake system and power
steering both use the power steering pump. If this ever
happens, let up on the brake pedal a little. When
you let up on the brake pedal in that situation, it lets the
steering get a little more help from the pump.
4-4