• Diesel engine scan tools help you diagnose and repair engine problems.Kim Steele/Photodisc/Getty Images
  
  A diesel engine is a type of internal combustion engine that uses a gas compressor to burn diesel fuel, which starts the ignition process. A scan tool is a type of diagnostic tool that communicates with your engine control unit (ECU) to determine what is wrong with your vehicle. You can also use these tools to clear your error codes once you fix the problem.
  
  

GRAPHIQ

• The Pro-Link GRAPHIQ Start Kit is designed for diesel engines and heavy-duty systems, and this tool helps you diagnose issues with Society of Automotive Engineers (SAE) and Technology systems and The Maintenance Council (TMC) of the American Trucking Association systems. This tool features plug-and-play technology, which means that your system recognizes the tool as soon as you plug it in, and it outputs this information on the device's display. You can use this tool to run tests on emissions, anti-lock brake systems (ABS) and body control systems, and you can obtain real-time data on your vehicle. This tool will create up to four graphs of captured data, and it shows up to eight lines of data on one screen. The product number for this tool is 616001, and it costs between $3,800 and $4,230 in 2010.
  
  

Scan Tool

• The AutoEnginuity Scan Tool is designed for both industry professionals and consumers, and it is a software program that installs on your laptop, pocket personal computer (PC) or Windows Mobile device. This tool allows you to capture freeze-frame data, which is data taken at one particular moment in time, and you can compare this data to current, historical or future performance. This tool allows you to capture and clear diagnostic trouble codes (DTCs), and you can log all of your data. The AutoEnginuity Scan Tool displays data in either the English or Metric measuring system, and it also has a plug-and-play interface, which plugs into the Universal Serial Bus (USB) port on your computer. As of 2010, this product costs about $250.
  
  

DT7 Diagnostic Package

• The DT7 Diagnostic Package allows you to run tests on your truck's diesel engine, and the package uses software that uploads to your laptop. This tool allows you to test original equipment manufacturer (OEM) systems. This tool allows you to transfer data to your computer via either a wireless or USB connection, and you can save or print out statistical information. There is a one-year warranty on this tool, and free software updates for one year. As of 2010, this product costs approximately $17,000.