How to Repair a 2003 BMW

1. Locate the OBD-II port located underneath the steering column on your 2003 BMW. If you are unable to locate the port on your own, consult your vehicle's owner's manual.
2. Plug the code scanner into the OBD-II port, then turn on your car's ignition so the engine is idling and the electrical system is activated.
3. Watch the display on the code scanner as it scans for any error codes that your onboard diagnostic system may be outputting. Note these codes and bring them to your local auto parts store or BMW dealership who can de-code them for you and tell you what in your 2003 BMW is failing.