Chapter 3 Brake Tools, Shop Equipment, and Service Information 39 Copyright by Goodheart-Willcox Co., Inc. and directly operate the hydraulic pump motor and sole- noids in the hydraulic actuator. Forcing a component to operate allows you to determine the condition of the com- ponent and related wiring. Types of Scan Tools Some scan tools can be used with the computer control sys- tems installed on only one manufacturer’s vehicles, and can- not be used to diagnose the systems of other manufacturers. Th ese are called dedicated scan tools. Th e earliest types of these tools could be used for trouble code retrieval only. Multi-system scan tools and generic scan tools can be used to diagnose the systems of many diff erent manufactur- ers. Th ese scan tools make use of specialized cartridges and cables that are changed to match the vehicle being worked on. Some scan tools contain all internal information, and can be updated by an interface with a desktop or laptop computer or over a phone line to the manufacturer. Scan tools with this feature have a special terminal that can be connected to a phone line. Most of the latest scan tools are bi-directional. A bi-directional scan tool is able to retrieve information from the vehicle computer, and can send data into the com puter. Th is ability to transfer data two ways allows the scan tool to operate anti-lock brake and traction control components for diagnosis, and to reprogram the computer if updates are necessary. Scan Tool Construction Scan tools are small and light enough to be hand-held. All scan tools have a keypad with a set of function keys used to select various functions, Figure 3-29. Typical function keys include enter and exit keys, arrow keys, and number keys. Many scan tools have specialized keys to access specifi c diag- nosis areas, or to interface with a remote computer or printer. Most scan tools have a liquid crystal display (LCD) that can vary in defi nition, size, and shape. All the information generated by the scan tool, as well as menus and command functions, are displayed on this screen. Some scan tools have a light emitting diode (LED) or low-defi nition liquid crystal display. Newer scan tools have high-defi nition LCD displays that can show graphs and waveforms, just like an engine analyzer’s oscilloscope. Th e display screen is used to display a menu which shows all possible scan tool functions, oft en called diagnostic routines. Th e technician can pick one of these to begin using the scan tool. Some scan tools have indicator lights to tell the technician that the scan tool is operating, what mode the system is operating in, or to indicate an obvious system defect. Various cables and adapters are provided with the scan tool to allow it to be attached to one or more data link con- nectors. Some scan tools also have battery clips or a ciga- rette lighter adapter to allow them to use the vehicle battery as a power source. Typical cables and adapters are shown in Figure 3-30. A few scan tools have an internal backup battery. Depending on the type of scan tool, it can have a variety of terminals to connect to other external devices, such as computerized analyzers. Scan Tool Cartridges and Software Th e scan tool, like a desktop computer, must have soft ware in order to function. As manufacturers included greater self-diagnostic capability on more vehicle systems, techni- cians needed additional tools that could monitor and test all these systems. Tool manufacturers began off ering scan tools that used small soft ware cartridges oft en no larger than a deck of cards. While these program cartridges allowed scan tools to monitor and control more system functions, there were some drawbacks. As new vehicle models came out or if a mid-year change was made to a vehicle system, the old program car- tridges could not be updated and had to be replaced. Scan tool manufacturers fi nally off ered a solution to this problem with generic cartridges, sometimes referred Goodheart-Willcox Publisher Figure 3-29. Typical scan tool keypad. Some scan tools may use different keys and configurations.