How you read E36 fault codes depends on OBD-I vs OBD-II, and US cars split on the 1996 model year — 1995-and-earlier are OBD-I, 1996-and-later OBD-II (a few very early '96 cars built in late '95 are still OBD-I, so confirm by build date).
- The round 20-pin connector under the hood is on BOTH and carries the full BMW data
- The 16-pin OBD-II port under the dash exists only on 1996+ and carries generic emissions data
A generic OBD-II scanner works only on 1996+ cars; to pull full BMW codes you need INPA software or a Peake/BMW reader on the 20-pin connector.
The stomp test works on OBD-I only: ignition to position 2, engine off, then floor and release the accelerator five times within about five seconds — the check-engine light flashes four-digit codes (1444 means no faults). There's no stomp test on the OBD-II cars.