On-board diagnostics refers to the vehicle's internal self-diagnostic and reporting capability. It monitors sensors across the engine, transmission, and body network to detect faults, illuminating the check engine light when a parameter falls out of range. Technicians plug a scan tool into the OBD-II port under the dashboard to read standardized diagnostic trouble codes and view live sensor data.
Heard on the job
Plug the scanner into the OBD port and see what codes are throwing that check engine light.
Also heard as
- on-board diagnostics
- OBD-II
- OBD2