OBD Port (Diagnostic Connector)

It is required on petrol cars in the US since 1996 and in the EU since 2001, and diesels a few years later. It provides power, ground and network lines. Its location is usually within reach of the driver. Pin 16 provides battery power and pins 4 and 5 are grounds; CAN lines are on pins 6 and 14. A tester can quickly check whether the port has power. Insurance and fleet trackers often plug into this port.

The tool plugs in and communicates with the control units.

Leaving some dongles plugged in can drain the battery. Damaged pins prevent communication.