The diagnostic port, also known as OBD-II or OBD2 port, on Cadillac vehicles is located under the dashboard on the driver's side. Look under the dashboard right above the brake pedal.
The OBD-II diagnostic port or OBD port for short can be used to diagnose vehicle problems, reset codes, stream live sensor data, and reset warning messages. To gain access to advanced options, you will need a Cadillac Diagnostic Scanner since a generic OBD-II scanner can only read and clear check engine codes.
Most Cadillac, including ATS, Escalade, CTS, SRX, STS, XTS, CT6, XT5, have the On-board Diagnostic (OBD) port under the dashboard on the driver's side.
The diagnosis port will allow you to read and clear fault codes from the Engine Control Unit. If you have an All System Scanner for Cadillac, you will be able to read and clear codes from any module, including transmission, airbag SRS, transmission, climate control, ABS, traction control, and more.
A basic OBD-II scanner will only access trouble codes related to the engine. It will not show any other fault codes even if warning lights are on.