Car OBD2 Communication Control Board

YCTECH industrial product control board development includes industrial control board software design, Car OBD2 Communication Control Board, software upgrade, schematic diagram design, PCB design, PCB production and PCBA processing located in the east coast of China. Our company designs, develops and manufactures industrial Internet of Things control board. Abstracting the application of the Internet of Things in the industrial industry, we can summarize it into four levels: data collection and display, basic data analysis and management, in-depth data analysis and application, and industrial control.

You've probably encountered OBD2 already:

Ever noticed the malfunction indicator light on your dashboard?

That is your car telling you there is an issue. If you visit a mechanic, he will use an OBD2 scanner to diagnose the issue.

To do so, he will connect the OBD2 reader to the OBD2 16 pin connector near the steering wheel.

This lets him read OBD2 codes aka Diagnostic Trouble Codes (DTCs) to review and troubleshoot the issue.

The OBD2 connector

The OBD2 connector lets you access data from your car easily. The standard SAE J1962 specifies two female OBD2 16-pin connector types (A & B).

In the illustration is an example of a Type A OBD2 pin connector (also sometimes referred to as the Data Link Connector, DLC).

A few things to note:

The OBD2 connector is near your steering wheel, but may be hidden behind covers/panels

Pin 16 supplies battery power (often while the ignition is off)

The OBD2 pinout depends on the communication protocol

The most common protocol is CAN (via ISO 15765), meaning that pins 6 (CAN-H) and 14 (CAN-L) will typically be connected

On board diagnostics, OBD2, is a 'higher layer protocol' (like a language). CAN is a method for communication (like a phone).

In particular, the OBD2 standard specifies the OBD2 connector, incl. a set of five protocols that it can run on (see below). Further, since 2008, CAN bus (ISO 15765) has been the mandatory protocol for OBD2 in all cars sold in the US.

ISO 15765 refers to a set of restrictions applied to the CAN standard (which is itself defined in ISO 11898). One might say that ISO 15765 is like "CAN for cars".

In particular, ISO 15765-4 describes the physical, data link layer and network layers, seeking to standardize the CAN bus interface for external test equipment. ISO 15765-2 in turn describes the transport layer (ISO TP) for sending CAN frames with payloads that exceed 8 bytes. This sub standard is also sometimes referred to as Diagnostic Communication over CAN (or DoCAN). See also the 7 layer OSI model illustration.

OBD2 can also be compared to other higher layer protocols (e.g. J1939, CANopen).