There's a dirty little secret about the security codes on a 2015 (and later?) MDX. There aren't any! If your battery goes dead you'll get the prompt on your screen to press the "audio power" button two seconds, if that doesn't work input the security codes. Where is the audio power button? It's the little button to the right of the volume control knob. Who knew? I didn't , so I took the car to my dealer service dept. Press that little button a few seconds and all is well! The guy told me that there are no actual security codes on Acuras any more.