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ODB-II Connector Introduction

The DB9 to OBD-II adapter cable is a simple adapter to allow the EasySYNC range of CANbus products to mate to OBD-II interface connectors commonly used in automotive diagnostics.

What is ODB-II Connector

The DB9 end plugs directly into the EasySYNC CANPlus modules or any CANbus adapter that conforms to the CAN-inAutomation (CiA) DS102-2 pin-out. The OBD-II end plugs directly into an automotive diagnostic port. The cable functions only with the CANbus portion of the OBD-II specification. The Cable incorporates a standard DB9 Female connector and an OBD 16 Pin Male connector for communication between the EasySYNC CANbus products and OBD-II interface.

OBD stands for onboard built-in diagnostics. As the name implies, this is a built-in diagnostic system for all modern vehicles (after 1996). The system has a computer-based application program, which can monitor vehicle performance through your speed, mileage, fuel emission data, etc. Measure some important life parameters of engine. This complete system is called ECU (engine control unit). The OBD connector is only used by maintenance personnel to monitor the health of the vehicle and provide diagnosis. In addition, it can also control the warning lights on the dashboard.

ODB-II Datasheet

ODB-II Pinout &Configuration

Pin NumberPin NameDescription
1,3,8,9,11,12,13BlankThese pins are not standard and are vendor specific. It is also not required for normal communication/interfacing
2SAE J1850 Bus+This protocol uses Variable Pulse Width and is normally used by GM vehicles. This is the Bus positive pin of the protocol.
10SAE J1850 Bus-This protocol uses Variable Pulse Width and is normally used by GM vehicles. This is the Bus negative pin of the protocol.
4,5GroundGround of complete system of the Car including chassis
6ISO15765-4 CAN HighIt follows 2-wire CAN protocol at 1Mbps speed. This is the CAN high Pin
14ISO15765-4 CAN LowIt follows 2-wire CAN protocol at 1Mbps speed. This is the CAN low Pin
7ISO 9141 – K LineIt follows asynchronous serial communication protocol, this pin is the K line
8ISO 9141 – L LineIt follows asynchronous serial communication protocol, this pin is the L lin
ODB-II Pinout &Configuration

ODB-II pinout’s image is given, as well as the details shown in the table.

OBD2 pinout
OBD2 pinout

How does a ODB-II work?

How do I use the OBD-II connector on Arduino / raspberry Pi? It’s federal law to modify or tamper with the OBD system of the car, but if your engine fault light has appeared in the car, and you want to diagnose the problem by yourself, it’s very easy to connect your car with a microcontroller or microprocessor by using a connector like odb-ii. Once you enter all the important details of the car into a development platform such as Arduino or raspberry PI, the application is endless.

The OBD port can be found on the dashboard near the steering wheel of each vehicle. The location of the port varies from manufacturer to manufacturer and is usually hidden in a blind area for aesthetic reasons. After finding the port, hook the connector and connect the other end to the stn1110 OBD UART board. Then connect the UART board to the computer, and communicate with the ground pin through TX, RX on the computer. The normal data type will have 9600 baud rate, including 8 data bits and 1 stop bit, without parity. Then, we can use any serial communication software (such as putty, or even Arduino) to talk to the car through the at command. Each at command has a specific task to execute or return a specific value. You can learn more about the interface through the sparkfun webcast tutorial. Explains how to establish and start a connection.

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