What vehicle data can paly in OBD

The rise of the OBD connector in the automotive aftermarket has sprung up various mobile app applications. Thanks to the boom in big data and Internet of vehicles, we have spent a lot of money on crowdfunding and innovation platforms. What can a small OBD connector play.

In addition to the GPS (location, altitude, time) provided by the mobile phone and the derived speed and track, the OBD connector connected to the mobile phone through Bluetooth/WiFi can also obtain some data on the car, in general, there are three types:

* DTC, Diagnostic trouble code

* PID, parameter identification

* Did, data identification

DTC is not detailed. It is commonly known as the fault diagnosis code. It is worth mentioning. Generally, the number of DTC detected in the Controller on the vehicle is 2 ~ I/O pins 3 times higher than those of ECUs. In principle, any signal (mainly input) that exceeds the normal range during work should be automatically recognized by ECUs, the OBD interface is used to query devices outside the vehicle. Similar to the excessive blood check in an individual's physical examination.

The number of PIDs depends on the complexity of the algorithm. They are some status parameters of the Controller (RAM) during operation. The difference between the number of PIDs and DTC is that the number of IDCs is cleared after power loss, the original intention of the design is to cooperate with DTC for further online checks. It is similar to the question and answer during the health check.

Did is the identity of each ECU. It usually exists in ROM and reports the version number and manufacturer information. It is similar to the personal information on the medical records.

Of course, in addition to the above data, there are also CPID (Control Parameter Identification), but the car factory is generally not open to the outside (password verification is required), you can control ECU reset and execute specific procedures.

All of this data is not broadcast and needs to be queried through diagnostic protocols, which are divided into two layers: Transport Layer (ISO15765-2) and diagnostics (UDS, kwp2000, OBD, gmlan ). Generally, the transmission layer is uniform, and the definitions of different automobile manufacturers of diagnosis faults vary widely, but there is still a general part.

What vehicle data can paly in OBD