It appears you’re having trouble locating the OBD2 port on your 2001 BMW 745 (E38 model) and understanding the function of the 20-pin connector in the engine bay. Let’s clarify this for you.
You mentioned finding a 20-pin connector in your BMW E38’s engine compartment with several pins populated. This is indeed a diagnostic connector, and it’s typical for older BMW models. For your questions regarding this connector:
A) The 20-pin diagnostic connector in your BMW E38 can be used for scanning and accessing control modules. While it doesn’t use the OBD2 standard connector, it is a BMW-specific diagnostic interface. The pins you listed (1, 4, 7, 12, 14, 15, 16, 19, and 20) are likely sufficient for a compatible scanner to communicate with various modules, including potentially the airbag module you want to program or reset. The specific pins used will depend on the diagnostic tool and the module being accessed.
B) Regarding the OBD2 port location inside your 2001 BMW 745, it should be present. Despite your search behind the cover to the left of the cup holder yielding nothing, it’s highly probable that your E38, being a 1999 build (close to 2001 model year), is equipped with an OBD2 port as well. The location can sometimes be slightly obscured. Instead of solely focusing on the left of the cup holder, try looking underneath the dashboard on the driver’s side. Often, it’s located near the steering column or integrated into the lower dashboard trim panel. You might need to get down and look upwards to spot it. It might be tucked away, but it should be there, not behind the audio or climate control.
C) If you do locate an OBD2 contact inside your car, it will carry signals that are potentially different from the 20-pin connector in the engine bay. The OBD2 port is standardized and typically provides access to engine and emissions-related data as a minimum, but often also covers other modules like transmission, ABS, and sometimes even chassis and body systems depending on the vehicle and the scan tool capabilities. While it’s been said that OBD2 is only for emissions in some contexts, in practice, especially for models of your era, it’s generally more versatile than just emissions and could very well access the airbag module too, depending on the scan tool you use. It’s worth checking with an OBD2 scanner first as it’s the more modern and commonly supported interface.
In summary, for your 2001 BMW 745, you likely have both a 20-pin diagnostic connector under the hood and an OBD2 port inside the cabin, likely under the driver’s side dashboard. Start by thoroughly checking under the dash for the OBD2 port, as this is the more standard port for modern scanners and might provide the easiest access to the modules you need to communicate with.
