Modern cars have engines almost entirely controlled by electronics.  Ignition systems and fuel systems come immediately to mind.  They are electronically actuated, measured and controlled by a variety of devices, all connected to their overseer...the computer module.  And it's not just the engine anymore...the air conditioning system, the antitheft and locking systems...even the radio...can all be controlled electronically.

They all report to computers.  Some cars can have upwards of 20-30 different computers installed, all controlling different systems.  Some working together, some working alone.  A modern technician needs to be more of an IT expert with an Associates Degree in computer technology, than an old fashioned, grease under the fingernails, mechanic.  And you thought that "Check Engine" light was just an annoyance....

At the heart of finding the source of problems in these systems, it is mandatory that the technician have a means of connecting to the  appropriate system and finding out what the module in charge found wrong.  The tool used is called a scan tool, and it is a communications link between the technician and the electronic system he is attempting to repair.  Depending on the level of scan tool available, the tech may only be able to access basic information, or he may be able to not only access all the information, but command the related module to carry out its mission on request for testing, even reprogramming the module's software if allowed by the OEM.

This section of AutoServiceTech is devoted to providing information on choosing a scan tool, and using it to its full capabilities.  We will also include information on reprogramming, accessing factory information, and whatever other topic will help you to diagnose today's, and tomorrow's, cars faster and easier.

As always here at AutoServiceTech, please let us know what you thought, what you liked, what you'd like to see added.