• Professional auto mechanics diagnostic tools can pinpoint car trouble quickly and accurately.automobile engine image by palms from Fotolia.com
  
  When a car shows a warning light or develops an unusual noise, a mechanic uses professional auto mechanics diagnostic tools to pinpoint the trouble. Three different types of such professional tools are available: information tools, scanning tools and other hand-held tools.
  
  

Information Tools

• Today's cars have a diagnostic system called On-Board Diagnostics II or OBD II, which keeps track of the workings of the engine systems and the transmission. When this system generates a Diagnostic Trouble Code or DTC, the mechanic can look up the code definition from the manufacturer of the car, or can find it at specific websites on the Net. Another information tool is the diagnostic flow chart, which gives the mechanic a step-by-step guidance for testing issues difficult to diagnose. Diagnostic flow charts give the information the mechanic needs to find the problem by eliminating what works. Factory service bulleting can also be helpful to the mechanic in pinpointing trouble in a vehicle. They identify potential safety hazards and give the information necessary to fix them. Such bulletins make the mechanic aware of manufacturing defects and part failures and can pinpoint hard-to-repair issues for certain cars.
  
  

Scanning Tools

• All newer cars have a special plug for On Board Diagnostics II, or OBD-II under the dashboard, where the mechanic can interface with the vehicle to check emissions and other critical car systems. Trouble code readers are scanners that interface with the OBD-II plug and read the manufacturer's Diagnostic Trouble Codes. These readers are often tuned for specific makes of cars and trucks. Some of them come with software. After scanning the problem, the scanner plugs into a computer to let the mechanic know exactly what the problem is, a possible cause, repair instructions and the approximate cost. Other diagnostic scanning tools check emission problems only, or focus specifically on brake functioning. Some are available with printer capabilities.
  
  

Other Diagnostic Tools

• Common professional auto mechanics tools include vacuum test kits that test the vacuum the engine generates when it's running and pinpoints any blocking or breaks in the vacuum line. A vacuum test kit also comes with a brake-system bleed attachment, which can show whether brake fluid needs to be refilled. Fuel pressure gauges help the mechanic find any problems with the pressure in the fuel injection system. A simple test light is also a useful diagnostic tool, since it can show any problems in a vehicle's electrical circuits. These lights are excellent for testing wires, fuses and for checking the surface charge of a vehicle's batteries. For computer-related circuits, however, a mechanic will use a voltmeter or multi-meter. An IR or infrared meter uses an infrared beam to check the temperature and can show engine cylinder misfires, cooling system and air conditioning problems and also works to show exhaust system and heater malfunctions. Another diagnostic tool is an air pressure gauge to check the tire pressure.