Diesel Mechanics/Heavy Truck Maintenance

Career Diploma

Program Outline

Instruction Sets
Your program consists of Instruction Sets written to take you step-by-step through the knowledge and skills you'll use in your new career.

Computer Specifications
As you know this is an online academic program. This means you will need access to high-speed internet to begin your program. In addition, you will need access to a Microsoft® Windows® based computer running Windows 10® or later or an Apple® Mac® computer running macOS® or later, and an email account to complete this program with Penn Foster.

Here's how it works: You receive the first course as soon as your enrollment has been accepted, and other courses will follow as you complete your exams. You can earn your Career Diploma in as little as a year. Here is an overview of what you'll learn and the order in which you'll access your lessons:

Program Goal and Outcomes

Program Goal: To provide students with knowledge of skills ranging from basic diesel engine operations to troubleshooting and repair. Students will learn how to maintain and do repairs on their own trucks, work for a truck fleet or dealership, or start a full- or part-time business.

Program Outcomes:
Upon completion of the program, students will be able to:

  • Recognize the role of a diesel repair technician and the many exciting career opportunities available to skilled technicians
  • Identify common tools and shop safety procedures used in the repair of heavy-duty vehicles
  • Understand the basic operation of a diesel engine and its major components
  • Describe the operation of the cooling and lubrication systems of a typical diesel engine
  • Identify the various procedures used in the inspection and rebuilding of a typical diesel engine
  • Explain the operation of a mechanical fuel injection system, the fuel-delivery system, as well as the properties of the various types of diesel fuels
  • Recognize the basics of electrical and electronic engine control systems
  • Recognize the basic operation and repair of heavy-duty truck steering and suspension systems, along with service and repair of vehicle wheels and tires
  • Identify the operation of hydraulic and pneumatic braking devices and control systems, the interpretation of fault-indication messages, and the troubleshooting of brake system problems
  • Describe the operation and repair procedures for common heavy-duty truck drivelines, automatic transmissions, and manual transmissions and clutch systems
  • Recognize the function and operation of heating, ventilation, and air conditioning systems used on heavy-duty trucks
  • Explain the basic theory and repair of various electrical systems, including the battery, charging system, starting system, and lighting systems
  • Identify the safety practices and maintenance procedures for truck and trailer systems

Instruction Set 1

Starting Your Program
In this course, you’ll develop the necessary skills to ensure your success in the program. You’ll learn how you can improve your study skills, so you’re able to use a number of tools that will help you to be successful.


  • Identify skills needed to be a confident and independent online learner

Instruction Set 2

Orientation Diesel Mechanics/Heavy Truck Maintenance
As you start reading this first lesson, you’ll learn about the growing diesel-engine-powered vehicle repair field and the increasing need for professional technicians. You’ll discover the many exciting career opportunities that are available to skilled technicians. Finally, you’ll learn about the basic operation of engines and other vehicle systems.


  • Analyze the job roles, components, and mechanics associated with diesel truck maintenance

Instruction Set 3

Diesel Truck Operation, Safety, and Technology
This course will introduce you to the operations of diesel engines, including how the diesel cycle differs from other types of engine cycles, and how and why the diesel engine has been a popular choice for powering such a wide range of vehicles. The course covers several major diesel engine components and moves on to cover shop safety and tools.

You’ll learn about the different types of work environments in which diesel technicians work, such as those found in the trucking industry, diesel-powered locomotive repair shops, heavy-equipment repair shops, and nautical engine overhaul and maintenance facilities. As you’ll find, many other industries also employ technicians who maintain and repair diesel engines.

Finally, you'll learn about the work performed by diesel technicians. This work can vary and involves the knowledge of various vehicle components, including several engine systems and accessories. When a problem with an engine accessory occurs, a diesel technician is often required to locate and solve the issue.


  • Analyze the principles, components, and classifications of diesel engines
  • Identify the safety precautions, protective gears, and tools required by diesel technicians

Additional Course Materials:
Textbook: Diesel Engine Technology

Instruction Set 4

Diesel Engine Fundamentals
In this course, you’ll take a closer look at diesel engine components. In the first lesson, you'll familiarize yourself with the various components of engine blocks, crankshafts, and piston assemblies. In the second lesson, you'll be introduced to the various functions of the cylinder head, camshaft, and valve train components. Finally, this course will give you an overview of how various components of a diesel engine work and function.


  • Identify the various components of engine blocks, crankshafts, and piston assemblies
  • Categorize the various components of cylinder heads and camshafts as well as their servicing processes

Instruction Set 5

Truck Engine Lubrication, Cooling, and Exhaust Systems
This course continues your study of diesel engine systems. You’ll look at lubrication, cooling, air intake, and exhaust systems. You’ll soon find that lubricating systems are easy to comprehend once you understand the system’s components. You’ll also be able to understand how to properly maintain oil filters as well as how to recognize low oil situations. Along with this, you’ll also look at the functions of components related to engine breathing and troubleshoot components of the exhaust system.


  • Identify the purpose of lubrication and cooling systems in trucks
  • Categorize the various parts and purposes of truck engine air intake and exhaust systems

Instruction Set 6

Truck Fuel Systems
In this course, you’ll continue your study of diesel technology by looking at fuel and injection systems. You’ll learn about the different types, essential components, and methods of maintenance for fuel and injection systems.


  • Identify the major components of the diesel engine fuel system
  • Categorize the various components of the fuel injection system
  • Identify the major components of distributor injection pump and mechanical fuel injector systems

Instruction Set 7

Truck Electronics and Engine Controls
This course covers the basics of electricity and then moves on to diesel engine electrical systems, including the charging and starting systems. You'll then learn about electronic engine controls.

The information is divided into two lessons; the first lesson focuses on basic electrical theories, charging systems, and the diesel engine’s starting system. The second lesson describes each major component related to the computer control system of engines.


  • Categorize the electrical principles, troubleshooting methods, and starter-system functions related to the electrical systems of trucks
  • Identify the main operational and functional components related to the electronic engine controls of trucks

Instruction Set 8

Truck and Trailer Maintenance
This course provides an introduction to the trucking industry and details key career and certification information. You’ll also review safety practices and take another look at tools and measuring equipment.


  • Analyze the fundamentals of truck maintenance and the components of the trucking industry

Additional Course Materials:
Textbook: Truck and Trailer Systems

Instruction Set 9

Truck Electrical Systems
This course will introduce you to the electrical theories, types of batteries, system monitoring programs, and more such topics related to the truck’s electrical system. This course takes another look at basic electrical topics before moving on to cover truck electrical systems, such as starting and charging systems, lighting, and wiring. You’ll also study about the truck computer systems.


  • Categorize the theories, components, and elements related to the truck electrical systems
  • Identify the utility of the lighting system and starting system of trucks
  • Analyze the purpose of vehicle computer system, its maintenance, and the importance of system monitoring programs

Instruction Set 10

Truck HVAC Systems
This part of your program looks at truck heating, ventilation, and air-conditioning (HVAC) systems and auxiliary power units (APUs). In this course, you’ll learn about important truck HVAC control systems, how they operate, and how to maintain them. You’ll also spend some time reading about APUs and their purpose in conjunction with truck HVAC systems.


  • Analyze the components and maintenance of truck HVAC systems

Instruction Set 11

Tires, Suspension, and Steering
This part of your program deals with some of the systems and components that will most likely demand the bulk of your repair efforts. Tires and suspension systems, for example, wear out during much shorter intervals than parts such as engines. You’ll also cover wheels, frames, and steering and trailer systems.


  • Categorize the various types of tires, wheels, and the methods of maintaining them
  • Identify the purpose of suspension and steering systems

Instruction Set 12

Truck Brake Systems
This part of your program focuses on truck brake systems, an important topic for just about any heavy-duty truck technician. You’ll study different types of brake systems, their components, and how they work.


  • Categorize the different hydraulic and air brake systems and the methods of maintaining them
  • Identify the various parts and maintenance methods associated with air-brake and anti-lock brake systems

Instruction Set 13

Drivelines and Transmissions
This part of your program covers the driveline system, clutches, and drive axles before moving on to truck manual and automatic transmissions. You’ll learn about the major components, operation, and general procedures for servicing these systems.


  • Identify the functions, components, and methods of maintenance for the driveshaft, clutch, and axles
  • Analyze the components, functional aspects, and maintenance of the truck’s transmission
  • Identify the operational aspects and efficiency of the automatic transmission

Instruction Set 14

Troubleshooting and Repair
In this course, you’ll review engine- and electrical-system operating characteristics, as this knowledge forms the foundation on which all troubleshooting studies and skills are built.

The conclusion of your program focuses on troubleshooting practices as well as how to approach a problem by making the most of the tools and knowledge you’ve already gained. You’ll also cover preventive maintenance topics, including inspections and maintenance programs. Developing an effective approach to troubleshooting takes time, but it also requires having the right mindset.


  • Categorize the various operating principles and operational problems in a typical diesel engine
  • Compare various diagnostic methods used for fuel-injection system, lubrication system, valve system, and air-filtering system
  • Identify the various function of electrical system, starting system, and cooling system
  • Analyze the requirements of preventive measurement program and the testing procedures of oil analysis

Additional Course Materials:
Textbook: Troubleshooting and Repairing Diesel Engines


Online Library and Librarian
Students in Penn Foster College have access to an online library for use during their studies. Students can use this library to do the required research in the courses they complete or can use it for general reference and links to valuable resources. The library contains helpful research assistance, articles, databases, books, and Web links. A librarian is available to answer questions on general research-related topics via email and to assist students in research activities during their studies with Penn Foster College International.

We reserve the right to change program content and materials when it becomes necessary.

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