Diagnostic Connector on a Car

For cars before 2001 the ECU connector can either be inside the cabin or under the bonnet (hood). For the vast majority of cars 2001 onwards you will find the diagnostic socket in the interior. It will normally be within arm’s length from the driving seat and be a 16 pin D shaped female commonly referred to as an OBD2 socket. Common locations include – 

Under the dashboard (left, right or centre)

The best way to view is to be squatting outside the vehicle or leaning over from the passenger side. The connector may be exposed or behind a  plastic cover.  May also be accessible by removing a fusebox cover.

In the centre console

This will either be behind a blanking plate as on many Vauxhall/Opels or another removable item such as an ashtray. This is common on Volkswagen Audi cars. In some cases it may be further down the console between the gear lever and the handbrake.

With the ashtray removed the 16 pin diagnostic socket is visible on this early VW Sharan
Sides of the dashboard

Will be either side of the steering wheel behind a blanking plate

Diagnostic Connector on a Bike

On Motorbikes the diagnostic connector will not only vary greatly in location but also the type of connector. Usually look close to the area near the ECU. Under the driver seat, pillion seat or stowage area. The connector will typically be loose on the end of a cable as opposed to screwed into a fascia.  The connector can be a 16 pin OBD2 type (as on Triumph bikes), 10 pin round socket (as on BMW bikes), 6 pin (as on KTM bikes), 4 pin or a 3 pin type (as on many Italian and Japanese bikes). This is not written in stone so can vary. It will usually have a protective cover over it if it hasn’t been discarded by previous hands.

6 pin diagnostic connector on a KTM motorbike with blanking/protective plug still on