Paccar PX-9 User manual

Operator’s Manual
Operator s Manual’ 2022 Model Year Warranty
2021 Emissions

PX Operator Manual
PACCAR PX-9 Engine

Engine Operation..................................... 1
Engine Maintenance..................................... 2
Engine Warranty..................................... 3
Contents

© 2022 PACCAR Inc. - All Rights Reserved
This manual illustrates and describes the operation of features or equipment which may be either
standard or optional on this vehicle. This manual may also include a description of features and
equipment which are no longer available or were not ordered on this vehicle. Please disregard any
illustrations or descriptions relating to features or equipment which are not on this vehicle. PACCAR
reserves the right to discontinue, change specifications, or change the design of its vehicles at any
time without notice and without incurring any obligation. The information contained in this manual is
proprietary to PACCAR. Reproduction, in whole or in part, by any means is strictly prohibited without
prior written authorization from PACCAR Inc.
Contents

Chapter 1 | ENGINE OPERATION
Safety - Introduction..............................................................................................................................5
Emergency - What To Do If.................................................................................................................10
Operating Instructions.........................................................................................................................13
ENGINE OPERATION -
4 Y53-1185-1J1 (10/21)
1

Safety - Introduction
Using this Manual
Please take the time to get acquainted with
your vehicle by reading this Operator’s
Manual. We recommend that you read and
understand this manual from beginning to
end before you operate this equipment.
This manual contains useful information for
the safe and efficient operation of this
equipment. It also provides service
information, with an outline for performing
safety checks and basic preventive
maintenance inspections. When
replacement parts are needed, we
recommend using only genuine PACCAR
parts.
We have tried to present the information
needed to learn about functions, controls,
and operation—and to present it as clearly
as possible. Occasionally, you may need to
reference this manual, and we hope you
find is easy to use.
NOTE
After you've read this manual, it should
be stored in the cab for convenient ref-
erence and remain with this truck
when sold.
Your vehicle may not have all the features
or options mentioned in this manual.
Therefore, you should pay careful attention
to the instructions that pertain to just your
vehicle. In addition, if your vehicle is
equipped with special equipment or options
not discussed in this manual, consult your
dealer or the manufacturer of the
equipment.
There are several tools built into this
manual to help you find what you need
quickly and easily; first is the Table of
Contents. Located at the front of the
manual, this table arranges the subject
matter into chapters, which can be quickly
referenced using the numbers shown in the
outer margin. The first page of each
chapter presents a list of the major
subjects contained in that chapter. Cross-
referenced citations can also help you find
information. If more information on the
current subject is located elsewhere in the
manual, a cross-reference may be
provided, such as "see Safety Alerts on
page 5." Finally, you’ll find a helpful
index at the back of the manual, which lists
the subjects covered, alphabetically.
All information contained in this manual is
based on the latest production information
available at the time of publication. If you
find differences between your instruments
and the information in this manual, contact
an authorized PACCAR dealer. Kenworth
Truck Company reserves the right to make
changes at any time without notice.
Safety Alerts
Read and follow all of the safety alerts
contained in this manual. They are there
for your protection and information. These
alerts can help you avoid injury to yourself,
your passengers, and help prevent costly
damage to the vehicle. Safety alerts are
highlighted by safety alert symbols and
signal words such as WARNING,
CAUTION, or NOTE. Do not ignore any of
these alerts.
Warnings
ENGINE OPERATION - Safety - Introduction
Y53-1185-1J1 (10/21) 5
1

The safety message following this symbol
and signal word provides a warning against
operating procedures that could cause
death or injury. They could also cause
equipment or property damage. The alert
will identify the hazard, how to avoid it, and
the probable consequence of not avoiding
the hazard.
Example:
WARNING
Hot engine oil can be dangerous. You
could be burned. Let the engine oil
cool down before changing it. Failure
to comply may result in death, person-
al injury, equipment or property dam-
age.
Cautions
The safety message following this symbol
and signal word provides a caution against
operating procedures that could cause
equipment or property damage. The alert
will identify the hazard, how to avoid it, and
the probable consequence of not avoiding
the hazard.
Example:
CAUTION
Continuing to operate your vehicle with
insufficient oil pressure will cause seri-
ous engine damage. Failure to comply
may result in equipment or property
damage.
Notes
The message following this symbol and
signal word provides important information
that is not safety related but should be
followed. The alert will highlight things that
may not be obvious and is useful to your
efficient operation of the vehicle.
Example:
NOTE
Pumping the accelerator will not assist
in starting the engine.
Forward
This manual contains information for the
correct operation and maintenance of your
PACCAR engine. Read and follow all
safety instructions. Refer to the WARNING
in the General Safety Instructions on page
7. Keep this manual with the equipment.
If the equipment is traded or sold, give the
manual to the new owner.
The information, specifications, and
recommended maintenance guidelines in
this manual are based on information in
effect at the time of printing. PACCAR
reserves the right to make changes at any
time without obligation. If you find
differences between your engine and the
information in this manual, contact your
local PACCAR Authorized Repair Location
or write to:
PACCAR c/o PACCAR Engines
PO Box 1518 Bellevue, WA 98009
The latest technology and the highest
quality components were used to produce
this engine. When replacement parts are
needed, we recommend using only
genuine parts from PACCAR.
ENGINE OPERATION - Safety - Introduction
6 Y53-1185-1J1 (10/21)
1

NOTE
Warranty information including the
EPA and California Emission Warranty
is located in the section entitled “En-
gine Warranty.” Make sure you are fa-
miliar with the warranty or warranties
applicable to your engine.
Illustrations
Some of the illustrations found in this
manual are generic, and may not look
exactly like the parts or assemblies you
find installed on your vehicle.
When an illustration differs from what you
see physically present on your vehicle, the
language describing the procedure will still
be correct for your application.
General Safety Instructions
WARNING
Improper practices, carelessness, or
ignoring any warnings may cause
property damage, personal injury, or
death.
Before performing any repair, read and
understand all of the safety precautions
and warnings. The following is a list of
general safety precautions that must be
followed to provide personal safety. Failure
to follow these instructions may cause
death or injury. Special safety precautions
are included in the procedures when they
apply.
Keep in mind that even a well maintained
vehicle must be operated within the range
of its mechanical capabilities and the limits
of its load ratings. See the Weight Ratings
label on the driver's door edge.
Every new vehicle is designed to conform
to all Federal Motor Vehicle Safety
Standards applicable at the time of
manufacture. Even with these safety
features, continued safe and reliable
operation depends greatly upon regular
vehicle maintenance. Follow the
maintenance recommendations found in
the Preventive Maintenance section. This
will help preserve your investment.
Make sure your vehicle is in top working
condition before heading out on the road, it
is the responsible driver's duty to do so.
Inspect the vehicle according to the
Driver's Check List.
• Work areas should be dry, well lit,
well ventilated, free from clutter,
loose tools, parts, ignition sources
and hazardous substances.
• Wear protective glasses and
protective shoes when working.
• Wear protective gloves when
working with hot liquids or
surfaces.
• DO NOT wear loose-fitting or torn
clothing. Tie back and/or tuck in
long hair. Remove all jewelry when
working.
• Before beginning any repair,
disconnect the battery (negative [-]
cable) and discharge any
capacitors.
• Put a “DO NOT OPERATE” tag in
the operator's compartment or on
the controls.
• Allow the engine to cool before
slowly loosening the coolant fill cap
to relieve the pressure from the
cooling system.
ENGINE OPERATION - Safety - Introduction
Y53-1185-1J1 (10/21) 7
1

WARNING
Removing the fill cap on a hot engine
can cause scalding coolant to spray
out and burn you badly. If the engine
has been in operation within the previ-
ous 30 minutes, be very careful in re-
moving the fill cap. Protect face,
hands, and arms against escaping flu-
id and steam by covering the cap with
a large, thick rag. DO NOT try to re-
move it until the surge tank cools down
or if you see any steam or coolant es-
caping. Always remove the cap very
slowly and carefully. Be ready to back
off if any steam or coolant begins to
escape. Failure to comply may result
in death, personal injury, equipment or
property damage.
• Always use wheel chocks or proper
jack stands to support the vehicle
or vehicle components before
performing any service work. DO
NOT work on anything that is
supported only by lifting jacks or a
hoist. Before resting a vehicle on
jack stands, be sure the stands are
rated for the load you will be
placing on them.
• Before removing or disconnecting
any lines, fittings, or related items,
relieve all pressure in the air, oil,
fuel, and cooling systems. Remain
alert for possible pressure when
disconnecting any device from a
system that contains pressure.
High-pressure oil or fuel can cause
death or personal injury.
• Always wear protective clothing
when working on any refrigerant
lines and make sure that the
workplace is well ventilated.
Inhalation of fumes can cause
death or personal injury. To protect
the environment, liquid refrigerant
systems must be properly emptied
and filled using equipment that
prevents the release of refrigerant
gas. Federal law requires capturing
and recycling refrigerant.
• When moving or lifting any heavy
equipment or parts, make sure to
use proper techniques and
assistance. Ensure all lifting
devices such as chains, hooks, or
slings are in good condition and
are of the correct load capacity.
Make sure all lifting devices are
positioned correctly.
• Corrosion inhibitors and lubricating
oils may contain alkali. DO NOT
get the substance in eyes and
avoid prolonged or repeated
contact with skin. DO NOT
swallow. If ingested, seek
immediate medical attention. DO
NOT induce vomiting. In case of
contact, immediately wash skin
with soap and water. In case of
harmful contact, immediately
contact a physician. Always keep
any chemicals OUT OF REACH
OF CHILDREN.
• Naphtha and Methyl Ethyl Ketone
(MEK) are flammable materials and
must be used with caution. Follow
the manufacturer's instructions to
ensure safety when using these
materials. Always keep any
chemicals OUT OF REACH OF
CHILDREN.
• When working on the vehicle, be
alert for hot parts on systems that
have just been turned off, exhaust
gas flow, and hot fluids in lines,
tubes, and compartments. Contact
with any hot surface may cause
burns.
• Always use tools that are in good
condition. Make sure you have the
ENGINE OPERATION - Safety - Introduction
8 Y53-1185-1J1 (10/21)
1

proper understanding of how to use
the tools before performing any
service work. Use only genuine
replacement parts from PACCAR.
• Always use the same fastener part
number (or equivalent) when
replacing items. DO NOT use a
fastener of lesser quality if
replacements are necessary. (e.g.,
DO NOT replace an SAE 10.9
grade with 8.8 grade fastener.)
• Always torque fasteners and fuel
connections to the required
specifications. Overtightening or
under-tightening can allow leakage.
• Close the manual fuel valves prior
to performing maintenance and
repairs, and when storing the
vehicle inside.
• DO NOT perform any repair when
impaired, tired, fatigued, or after
consuming alcohol or drugs that
can impair your functioning.
• Some state and federal agencies in
the United States of America have
determined that used engine oil
can be carcinogenic and can cause
reproductive toxicity. Avoid
inhalation of vapors, ingestion, and
prolonged contact with used engine
oil.
• DO NOT connect the jump starting
or battery charging cables to any
ignition or governor control wiring.
This can cause electrical damage
to the ignition or governor.
• Coolant is toxic. If not reused,
dispose of coolant in accordance
with local environmental
regulations.
CAUTION
Corrosive chemicals can damage the
engine. DO NOT use corrosive chemi-
cals on the engine. Failure to comply
may result in equipment or property
damage.
California Proposition 65 Warning
• Diesel engine exhaust and some of
its constituents are known to the
State of California to cause cancer,
birth defects, and other
reproductive harm.
• The catalyst substrate located in
the Diesel Particulate Filter (DPF)
contains vanadium pentoxide,
which has been determined by the
State of California to cause cancer.
Always wear protective clothing
and eye protection when handling
the catalyst assembly. Dispose of
the catalyst in accordance with
local regulations. If catalyst
material gets into the eyes,
immediately flood eyes with water
for a minimum of 15 minutes. Avoid
prolonged contact with skin. In
case of contact, immediately wash
skin with soap and water. In case
of harmful contact, immediately
contact a physician.
• Other chemicals in this vehicle are
also known to the State of
California to cause cancer, birth
defects or other reproductive harm.
• Battery posts, terminals, and
related accessories contain lead
and lead compounds, chemicals
known to the State of California to
cause cancer and reproductive
harm. Wash hands after handling.
ENGINE OPERATION - Safety - Introduction
Y53-1185-1J1 (10/21) 9
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Emergency - What To Do If
Roadside Assistance
Open 24 hours a day, 365 days a year, call
toll-free to talk to someone at the PACCAR
Customer Center:
• Kenworth customers:
1-800-KW-Assist
(1-800-592-7747)
• Peterbilt customers:
1-800-4Peterbilt
(1-800-473-8372)
The PACCAR Customer Center
• Uses a custom mapping system
that locates PACCAR Powertrain
distributors and Independent
Service Providers (ISPs) near you,
listing services offered, hours of
operation, and contact information.
• Assists with jump and pull starts,
tires, trailers, fines and permits,
chains, towing, hazardous clean-
up, out of fuel (roadside),
mechanical repairs and preventive
maintenance services.
• Employs multilingual agents and
has access to a translation service,
ensuring quality assistance for
customers in any language.
• Places you in contact with a
PACCAR Powertrain distributor
who can answer your warranty
questions.
• Provides these services for FREE.
Stop Engine Lamp
12
The stop engine warning lamp will
illuminate, and an audible tone will sound,
when a major engine problem exists. Your
vehicle will be equipped with one of the
indicators above, 1 or 2, depending on the
engine model.
WARNING
If the Stop Engine warning lamp illumi-
nates, it means you have a serious en-
gine system problem. This should be
considered an emergency. You should
stop the vehicle as safely as possible
and turn OFF the ignition. The vehicle
must be serviced and the problem cor-
rected before driving again. Failure to
comply may result in death, personal
injury, equipment or property damage.
For engines with the engine-protection
shutdown feature enabled, the stop engine
lamp will begin to flash 30 seconds before
the engine automatically shuts down. The
warning lamp alerts the operator to the
impending shutdown.
The lamp will also illuminate when the DEF
tank is almost empty or the soot level in the
DPF is at full capacity. At this level
warning, regeneration cannot be performed
and engine power will be derated.
Engine may automatically shut down if the
check engine lamp and stop engine lamp
are illuminated and the operator does not
correct the condition.
ENGINE OPERATION - Emergency - What To Do If
10 Y53-1185-1J1 (10/21)
1

Engine Oil Pressure Lamp Turns
On
It is important to maintain oil pressure
within acceptable limits. If oil pressure
drops below the minimum psi a red
warning lamp on the oil pressure gauge
and the Stop Engine Lamp will come ON.
CAUTION
Continuing to operate your vehicle with
insufficient oil pressure will cause seri-
ous engine damage. Failure to comply
may result in equipment or property
damage.
• If the oil pressure fails to rise within
10 seconds after the engine starts,
stop the engine and determine the
cause.
• See Engine Oil Specification for the
correct oil pressure ranges for your
vehicle's engine.
• If the oil pressure suddenly drops,
or the audible alarm and engine oil
pressure warning light come on
while driving, do the following:
1. Slow down carefully.
2. Move a safe distance off the road
and stop.
3. Place the transmission in neutral
(N) and set the parking brake. (See
Parking Brake Valve and Operating
the Transmission in your vehicle
Operator's Manual, for
transmission shifting and parking
brake information.)
4. Turn OFF the engine.
5. Turn ON the emergency flasher
and use other warning devices to
alert other motorists.
6. Wait a 15-20 minutes to allow oil to
drain into the engine oil pan, and
then check the oil level. See
Engine Oil Level.
7. Add oil if necessary. If the problem
persists, contact an authorized
PACCAR engine dealer as soon as
possible.
Check Engine Lamp Turns On
Or
Check Engine Lamp - Turns on when a
problem exists, but the vehicle can still be
safely driven. Vehicle should be serviced to
correct the problem but the situation should
not be considered an emergency.
The lamp will also illuminate when a DPF
regeneration or addition of diesel exhaust
fluid (DEF) is required. Another function of
the check engine lamp is to warn the
operator of an impending idle shutdown.
When the idle shutdown timer is 30
ENGINE OPERATION - Emergency - What To Do If
Y53-1185-1J1 (10/21) 11
1

seconds from expiring, the ECM begins
flashing the check engine warning lamp
once per second. When the timer expires,
the ECM will turn off the warning lamp and
shut down the engine.
Engine is Overheating
CAUTION
The cooling system may overheat if
the engine coolant is at the minimum
level. A sudden loss of coolant,
caused by a split hose or broken hose
clamp could also lead to an overheat
condition. Always inspect to ensure
hoses and clamps are not cracked,
worn, or loose. Failure to comply may
result in equipment or property dam-
age.
NOTE
The system may also temporarily over-
heat during severe operating condi-
tions such as:
• Climbing a hill on a hot day
• Stopping after high-speed/high-
load driving
• Debris blocking air flow through
the cooling module (radiator)
If the engine coolant temperature warning
lamp comes on and the audible alarm
sounds showing an overheat condition, or
if you have any other reason to suspect the
engine may be overheating, DO NOT
TURN OFF THE ENGINE unless a low
water warning device indicates a loss of
coolant.
Follow these steps if the engine coolant
temperature is rising, or the temperature is
already above normal, and there are no
other warning alarms displayed in the
instrument cluster.
NOTE
The instrument cluster gauges may
appear, if hidden from view, change
brightness and change color to bring
attention to a particular system.
1. Reduce engine speed, or stop.
When stopped, place the
transmission in neutral (N) and set
the parking brake. Keep the engine
running.
ENGINE OPERATION - Emergency - What To Do If
12 Y53-1185-1J1 (10/21)
1

WARNING
To reduce the chance of personal in-
jury, vehicle damage, and/or death
from overheated engines, which can
result in a fire, never leave the engine
idling without an alert driver present. If
the engine does overheat, as indicated
by the engine coolant temperature
lamp, immediate action is required to
correct the condition. Continued unat-
tended operation of the engine, even
for a short time, may result in serious
engine damage or a fire. Failure to
comply may result in death, personal
injury, equipment or property damage.
WARNING
Removing the fill cap on a hot engine
can cause scalding coolant to spray
out and burn you badly. If the engine
has been in operation within the previ-
ous 30 minutes, be very careful in re-
moving the fill cap. Protect face,
hands, and arms against escaping flu-
id and steam by covering the cap with
a large, thick rag. DO NOT try to re-
move it until the surge tank cools down
or if you see any steam or coolant es-
caping. Always remove the cap very
slowly and carefully. Be ready to back
off if any steam or coolant begins to
escape. Failure to comply may result
in death, personal injury, equipment or
property damage.
NOTE
Keep the engine running at idle speed
unless a warning icon turns on that re-
quires the engine to be shut off.
2. Check to ensure the Oil Pressure
Gauge reads normal.
3. Make sure the engine fan is turning
by switching the Engine Fan
Switch from AUTO to MAN
(Manual).
4. Idle the engine to see if this
reduces the coolant temperature. If
the temperature does not begin to
drop, shut off the engine and
contact your nearest authorized
dealer.
5. If the temperature begins to return
to normal, allow the engine to idle 3
to 5 minutes before shutting it off.
This allows the engine to cool
gradually and uniformly.
6. If overheating came from severe
operating conditions, the
temperature should have cooled by
this time. If it has not, stop the
engine and let it cool before
checking to see if the coolant is
low.
7. Be sure the vehicle is parked on
level ground or the readings may
be incorrect. Check the coolant
level at the coolant surge tank.
Check the coolant level after each trip
when the engine has cooled. The coolant
level should be visible within the surge
tank. Add coolant if necessary.
Operating Instructions
Engine Warning Lamps
The following engine warning lamps
section covers only the lamps controlled by
the engine’s Electronic Control Module
(ECM). Please refer to the vehicle
“Operator's Manual” and “Engine
Aftertreatment Systems” manuals for
additional warning lamp information.
ENGINE OPERATION - Operating Instructions
Y53-1185-1J1 (10/21) 13
1

CAUTION
The installation of electronic devices to
the On Board Diagnostics (OBD) con-
nector, the vehicle Controller Area Net-
work (CAN), or their associated wiring
is not permitted. Doing so can ad-
versely affect vehicle performance
and/or cause fault codes to be record-
ed. The OBD connector is provided for
temporary connection of service tools
and for diagnostic purposes only.
Stop Engine Lamp
12
The stop engine warning lamp will
illuminate, and an audible tone will sound,
when a major engine problem exists. Your
vehicle will be equipped with one of the
indicators above, 1 or 2, depending on the
engine model.
WARNING
If the Stop Engine warning lamp illumi-
nates, it means you have a serious en-
gine system problem. This should be
considered an emergency. You should
stop the vehicle as safely as possible
and turn OFF the ignition. The vehicle
must be serviced and the problem cor-
rected before driving again. Failure to
comply may result in death, personal
injury, equipment or property damage.
For engines with the engine-protection
shutdown feature enabled, the stop engine
lamp will begin to flash 30 seconds before
the engine automatically shuts down. The
warning lamp alerts the operator to the
impending shutdown.
The lamp will also illuminate when the DEF
tank is almost empty or the soot level in the
DPF is at full capacity. At this level
warning, regeneration cannot be performed
and engine power will be derated.
Engine may automatically shut down if the
check engine lamp and stop engine lamp
are illuminated and the operator does not
correct the condition.
Engine, Check Engine
Or
Illuminates when a non emissions related
problem exists, but the vehicle can still be
safely driven. Vehicle should be serviced to
correct the problem but the situation should
not be considered an emergency.
Malfunction Indicator Light (MIL)
This warning light turns on when an engine
emissions failure occurs. An emissions
failure is not an emergency, and the
vehicle can be safely driven, but should be
serviced to correct the problem. In some
cases, the MIL will activate in conjunction
with the High Exhaust System Temperature
ENGINE OPERATION - Operating Instructions
14 Y53-1185-1J1 (10/21)
1

(HEST), diesel particulate filter (DPF), and
Diesel Exhaust Fluid (DEF) warning lights.
NOTE
The Malfunction Indicator Light (MIL)
turns on if the on-board diagnostics
(OBD) system detects a possible
emissions system failure. To ensure
the condition is corrected, the vehicle
should be brought in for service at the
earliest opportunity.
Diesel Particulate Filter (DPF)
This warning means that the DPF needs to
be regenerated and will appear when soot
in the DPF exceeds an acceptable amount
or significant amounts of hydrocarbons
(HC) are detected.
DPF Warning Light States
State Condition and Actions
White
Soot is above the acceptable
amount.
The DPF can be regenerated.
Amber
Soot almost fills the DPF OR
A significant amount of HC are
detected in the DPF.
The DPF should be regenerated to
prevent derate. If due to HC, warning
will be accompanied by a "DPF
Warmup" popup (see ).
Flashing
Amber
Soot has filled the DPF.
The EAS will now derate the engine.1
A parked regeneration must be
performed (see ).
Flashing
Red DPF is critically full.
State Condition and Actions
The EAS will further derate the
engine.2 The DPF can no longer be
regenerated and must now be
removed and cleaned.
Each progressing stage is accompanied by
an audible alert and a popup notification.
Routine automatic regenerations are
usually sufficient to eliminate the
accumulated soot, but when the conditions
for an automatic regeneration cannot be
met, or there are high levels of soot in the
DPF, a parked regeneration might be
required (see Automatic Regeneration or
Parked Regeneration).
This warning may also appear if the
system is attempting to regenerate
automatically while the vehicle is in Power
Take-off (PTO) mode.
1Emergency vehicles are exempt from this derate.
2Emergency vehicles are exempt from this derate.
ENGINE OPERATION - Operating Instructions
Y53-1185-1J1 (10/21) 15
1

High Exhaust System Temperature
(HEST)
WARNING
If the High Exhaust System Tempera-
ture (HEST) warning light is on, do not
park near people. The heat generated
by the engine aftertreatment system
(EAS) may cause serious burns if EAS
components are contacted. Failure to
do so may result in property damage,
personal injury, or death.
WARNING
If the High Exhaust System Tempera-
ture (HEST) warning light is on, do not
park near combustible vapors or mate-
rials. You must keep combustibles at
least 5 ft. (1.5 m) away from the ex-
haust (outlet) stream as it exits the tail
pipe while the HEST light is illuminat-
ed. Failure to do so could ignite an ex-
plosion and cause serious injury to by-
standers.
WARNING
When the High Exhaust System Tem-
perature (HEST) warning light is on,
the temperature of the tailpipe, ex-
haust pipes, diesel particular filter
(DPF)/selective catalytic reduction
(SCR) device and surrounding compo-
nents (including enclosures and steps)
becomes elevated and can cause seri-
ous burns to the skin. Allow adequate
cooling time before approaching, or
working on or near, any part of the ex-
haust system or surrounding compo-
nents. Failure to do so may result in
property damage, personal injury, or
death.
The purpose of the High Exhaust System
Temperature (HEST) warning light is to
notify the operator to high temperatures in
the vicinity of the tail pipe, diesel
particulate filter (DPF), and surrounding
components during a regeneration. The
HEST warning light turns on only when the
vehicle is stationary or moving slowly: less
than 5 mph (8 kph).
During a regeneration, some EAS
components can reach temperatures
greater than 1202°F (650°C). Therefore, it
is important to
Pay attention to the HEST warnings
prior to, during, and immediately
following a regeneration.
Diesel Exhaust Fluid (DEF) Lamp
The engine aftertreatment system includes
a diesel exhaust fluid (DEF) warning lamp
on the DEF gauge and additional warning
lamps or popup messages in the
instrument cluster. Refer to the operator
manual for more details.
The engine aftertreatment system includes
diesel exhaust fluid (DEF) warning lamps
or popup messages in the instrument
cluster. Refer to the operator manual for
more details.
DEF Warning Lamp in Instrument Cluster
The system will alert the operator when the
fluid in the DEF tank reaches a low level.
Refer to the operator manual for more
ENGINE OPERATION - Operating Instructions
16 Y53-1185-1J1 (10/21)
1

details. If the lamp illuminates but the level
is full, seek service immediately for DEF
fluid quality or DEF equipment repair.
Engine Wait-to-Start Light
This warning icon will appear when the
system needs some time before attempting
to start the engine. The light will illuminate
at key ON, and will stay on for a period of
up to 30 seconds.
NOTE
The length of time the 'Wait-To-Start'
lamp remains illuminated depends on
the ambient temperature. The lower
the ambient temperature, the longer
the lamp will be illuminated.
Once the Wait-to-Start light turns off, turn
the key to the starting position to start the
engine.
You may see this appear if the system has
detected a situation where the starter is too
hot and needs to cool down. Alternatively,
you may see it when the engine grid heater
is on and needs some time to warm up.
NOTE
Some engines are equipped with an
engine starting motor protection fea-
ture. If the starting motor is engaged
for 30 or more seconds, without the
engine starting, the starter will be
locked out from operating, allowing for
proper cooling of the starting motor.
During this time, the 'Wait-To-Start'
lamp will flash for 2 minutes. Once the
lamp stops flashing, the starting motor
will be allowed to function.
Engine Braking System
An engine compression brake is standard
on the PX-9 engines. Optionally, this
engine may be equipped with an exhaust
brake. When activated, these devices
supplement the service brakes by creating
a braking effect on the drive wheels,
helping keep your vehicle's service brakes
from overheating and/or from additional
wear and tear. The engine compression
brake or exhaust brake is not an
emergency brake nor intended to replace
the service brakes.
WARNING
DO NOT operate the engine compres-
sion brake or exhaust brake when driv-
ing/operating your vehicle bobtail or
with a loaded or unloaded trailer on
road surfaces with poor traction (wet,
icy, or snow covered roads) or in
heavy traffic. There may not be
enough weight on the rear axle to pro-
vide traction. Braking caused by the
normal operation of the engine com-
pression brake or exhaust brake could
cause you to lose control of the vehi-
cle, resulting in an accident. Make
sure the engine compression brake or
exhaust brake is switched "OFF" when
driving bobtail or with an unloaded
trailer. Failure to comply may result in
death, personal injury, equipment, or
property damage.
ENGINE OPERATION - Operating Instructions
Y53-1185-1J1 (10/21) 17
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