The BMW E46 is another name for the 3-Series vehicles produced between 1999 and 2005. Each BMW E46 is equipped with an internal computer that monitors a variety of aspects of the engine system. When the computer detects a potential problem concerning the vehicle's emission and exhaust system, the exhaust emission valve warning light will be illuminated on the instrument cluster. After the problem causing the light to come on has been resolved, the light will automatically turn off in many cases. Otherwise, it can be manually reset using a BMW diagnostic scanning tool.
Open the bonnet. Prop the bonnet open with the retaining bar.
Twist off the cap of the diagnostic port, located in the engine compartment below the windshield on the passenger's side.
Plug the diagnostic tool connector into the diagnostic port.
Turn the ignition switch on. Press the power button on the diagnostic tool if it does not come on automatically. Wait for the tool to finish scanning the computer for trouble codes.
Press the "clear" or "erase" button on the diagnostic tool to reset the light.
Press the power button on the diagnostic tool to turn it off.
Turn the ignition switch off. Disconnect the diagnostic tool. Replace the cap covering the diagnostic port.
If the situation that caused the warning light to come on has not been resolved, it may come back on after resetting.