hey everyone! battery just replaced and i bought my car used a few years back without a code. wasn't interested in taking apart interior. called a local acura dealer and they walked me through getting the radio serial number via the radio buttons. pretty easy. here are the steps.
1.) Start by putting the key in the ignition and turn to the ON position. Basically dash board is lit up but do not turn the car over.
2.) Make sure radio is off.
3.) Press radio preset buttons 1 and 6 at the same time.
4.) Use your other hand and turn on the radio while holding down preset buttons 1 and 6.
5.) Display will show 4 numbers with a small "U" (upper, ie: 1234). After 5 seconds, the display will change and show another 4 numbers with a small "L" (lower, ie:5678). This will be repeated twice, then the dreadful "CODE" will show up.
6.) Put it together and your radio serial number is now 12345678.
this worked on my 03 TL, not sure about other years or navi units as i don't have one.
for those in the toronto area, to get the code, call the guys at acura of north toronto. they gave me the code right over the phone in about 10 sec after i gave them the serial number. other acura dealerships in the toronto area were looking to charge me $100 for the code, yeah right - lol.