NGVi is now more than natural gas. Welcome to the new Alternative Fuel Vehicle Institute – AFVi!

Vehicle Training Level 3 Heavy-Duty NGV Maintenance and Diagnostics Training

The number one challenge facing heavy-duty NGV technicians is how to distinguish between a fuel quality problem, a fuel system problem or an engine problem. This course is the only training available that treats these three elements as a system and helps technicians understand how they are interrelated.  Emphasis is placed on the safety knowledge and repair practices that are unique for Cummins heavy-duty natural gas engines.

The course covers the components of all CNG fuel systems (regardless of manufacturer), as well as all Cummins 6.7 Liter, 9 Liter and 12 Liter natural gas engines.

The course includes operational theory with interactive labs designed to increase skills.

The on-demand e-learning version of this training takes approximately 7 hours to complete.


NGV Essentials and Safety Practices

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E-Learning On-Demand Register

Who Should Attend?

  • Technicians with at least basic skills in heavy-duty vehicle repair, who will be maintaining, diagnosing and repairing NGVs.
  • Technicians familiar with the basic operation of vehicle diagnostic equipment.

Course Objectives

  • Recognize the complex relationships between fuel properties, fuel system, engine, and exhaust aftertreatment system for heavy-duty natural gas vehicles
  • Describe the maintenance, diagnostics, and repair recommendations for the low- and high-pressure components of a CNG fuel system
  • Summarize the function of fuel system diagnostics integration systems
  • Recognize conditions that require defueling versus depressurizing CNG fuel systems
  • Identify the unique components and explain the operation of Cummins natural gas engines and exhaust aftertreatment systems
  • Define maintenance intervals and required procedures unique to Cummins natural gas engines
  • Determine diagnostic tools required for Cummins natural gas engines
  • Interpret data for electrical related issues
  • Diagnose common engine malfunctions

Course Outline

Module 1 Introduction
Module 2 High-Pressure CNG Fuel System Diagnostics and Maintenance
Module 3 Low-Pressure CNG Fuel System Diagnostics and Maintenance
Module 4 CNG Vehicle Depressurizing and Defueling Review
Module 5 Introduction to Natural Gas Engines
Module 6 Cummins ISX12 G Engine Operation, Diagnostics and Maintenance
Module 7 Cummins ISX12N Engine Operation, Diagnostics and Maintenance
Module 8 Cummins L9N and ISL G Engine Operation, Diagnostics and Maintenance
Module 9 Cummins B6.7N Engine Operation, Diagnostics and Maintenance
Module 10 Common Engine Malfunctions


Instructional staff members of colleges, universities, private training organizations, fleets, dealers or manufacturers are not candidates for this course, but have numerous options for bringing AFVi’s training classes to their campuses or facilities. For more information, contact us at 800-510-6484.