OBDscanner

An OBD scanner is a device used to interface with a vehicle's on-board diagnostics system to retrieve diagnostic trouble codes (DTCs) and live sensor data. It can be a handheld unit or a mobile dongle paired with a smartphone app. The primary purpose is to help diagnose and monitor the health of a vehicle's engine and emissions systems.

OBD-II, standardized in the United States since 1996, specifies the connector (SAE J1962 16-pin) and common data protocols (CAN, ISO 9141-2, ISO 14230-4, SAE J1850). Most modern vehicles provide read access to DTCs, readiness monitors, and real-time data such as engine RPM, vehicle speed, coolant temperature, oxygen sensor readings, fuel trim, and mass air flow.

Functionality ranges from basic code reading and clearing to advanced data logging, live graphs, and emissions readiness checks. Some devices support only generic DTCs, while others access enhanced manufacturer-specific codes. Connectivity varies: standalone handheld scanners, Bluetooth or Wi‑Fi adapters that connect to smartphones or tablets, and USB interfaces for PCs.

Typical use involves locating the OBD-II port under the dashboard, connecting the scanner, turning the ignition to the ON position, and performing a read or scan. Codes can indicate problems such as misfires, sensor faults, or emission system issues. Interpreting codes usually requires the code definitions and sometimes additional data from live sensors. Limitations include incomplete data, overlapping codes, and the need for professional diagnosis for complex faults. OBD scanning is widely used by DIY enthusiasts and professionals for maintenance, repair, and compliance checks.