1997 523 eu model OBD2 connector

Under the bonnet L/h side. Forward and slightly to the left of the box with a '+' on the top, and almost next to the suspension turret. Large round screw cap retained by a central plastic lead. Mike.

Only problem it's not strictly OBD2 compliant and I've only ever seen Carsoft and one other Russian homebrew program talk to the ECU apart from BMW's own diags software. Same with the later E36s too.

JB

You're probably right. My mistake. The position I gave was for an E34, but 523 makes it an E39, in which case the OBD connector has a similar round screw top, but is on the right hand side, near the fillers for the w/screen washer reservoirs. AFAIK on the E39 they are OBD2 compliant. Mike.