● The method of ignition varies by vehicle model. Please refer to the service manual. Figure 3.1.4 Figure 3.1.5 5. When the scan tool is properly connected to the DLC, the units will start initializing and present you with the main menu interface. (See Figure 3.1.6) The Procedure of DTC Retrieval Figure 3.1.6 1. Once you've entered the OBD-II function, the scan tool automatically communicates with the on-board computer to determine the communication protocol. After it's confirmed, the link is established. (See Figure 3.2.1) ● A PROTOCOL is a set of rules and procedures for regulating data transmission between vehicles, and testing equipment.
Here are the five different types of protocols (ISO 9141, Keyword 2000, J1850 PWM, J1850 VPW and CAN) that are used by vehicle manufacturers.