Diesel Mechanics Curriculum Details

Penn Foster College can help you take the first step toward preparing for entry-level diesel mechanic jobs. The program is designed to help students prepare to sit for the Medium-Heavy Truck Certification Test upon completion of the program. Students can expect to learn about repairing diesel engines, brake systems, shop safety practices, and more.

Program Goal and Outcomes

Program Goal

The Diesel Mechanics/Heavy Truck Maintenance Career Diploma program provides students with knowledge of skills ranging from basic diesel engine operations to computerized truck management systems. 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.

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
  • List 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

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

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

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

You will learn about the different types of work environment where diesel technicians work, like the trucking industry, diesel-powered locomotive repair shops, heavy-equipment repair shops, nautical engine overhaul and maintenance facilities, and many other industries employ technicians who maintain and repair diesel engines.

You will also learn about the work performed by diesel technicians which vary and they involve the knowledge of various vehicle components, including several engine systems and accessories. When a problem with an engine accessory occurs, they’ll often be required to locate and solve the issue.


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

Additional Course Materials:
Textbook: Diesel Technology

In this course, you’ll take a closer look at diesel engine components. In the first lesson, you’ll be familiarized with the various components of engine blocks, crankshafts, and piston assembly. In the second part of this course, you’ll be introduced with the various functions of the cylinder head, camshaft, and valve train components. Finally, this course will help you to get an overview on how various components of a diesel engine works and functions.


  • Identify the various components of engine blocks, crankshaft, and piston assembly
  • Categorize the various components of cylinder heads and camshaft as well as their servicing process

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 the truck engine air intake and exhaust systems

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


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

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

The information is divided into two lessons; the first lesson focuses on basic electrical theories, the 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 electrical system of trucks
  • Identify the main operational and functional components related to electronic engine controls of trucks

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

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

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

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

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

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

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

Additional Details

  • Licensing and/or certification requirements for jobs in this field are not the same in every state and may include educational, testing, and/or experiential requirements beyond those offered in the Penn Foster Program. Prospective students should contact the state professional licensing board or similar regulatory body in the state(s) where they plan to work to determine their requirements before enrolling in this Program. Click here for contact information for state licensing/regulatory boards and certain industry licensing information.

    Penn Foster College is not approved or regulated as a school by the Maryland Higher Education Commission.

Penn Foster College Accreditation & Licensing Details

Penn Foster College has been nationally accredited for over 40 years, and has met the high standards of integrity and performance set by the Distance Education Accrediting Commission (DEAC) in Washington, D.C. Penn Foster College has been thoroughly reviewed and has earned several important accreditations and licensing. We also participate in the National Council for State Authorization Reciprocity Agreements.

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A Committed Support System

While you can study independently, you’re not alone! With a dedicated Student Services department, the Student Community, and instructors just a call away, you’ll have access to the support you need.

Progress Tracking and Goal Setting Tools

Our customizable goal-setting tools will help you create a schedule and stick to it. Need some extra time to complete a lesson? Not a problem — you can adjust your study plan at any time to set a pace that works for you.

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Student Community

Looking to connect with other Penn Foster students? Our Student Community is the perfect place for you to interact with your peers — as well as Penn Foster faculty and staff — to discuss your online learning experience, congratulate fellow students, and share your Penn Foster experience.

Sample Diesel Mechanic Lesson

Penn Foster courses are written in a way that is easy to understand, and materials are broken down into manageable lessons. Take a look at what a Diesel Mechanics/Heavy Truck Maintenance course would look like:

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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, Microsoft® Office 2019 or Microsoft 365®, and an email account to complete this program.
We reserve the right to change program content and materials when it becomes necessary.
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