How to Obtain the Audio Unit Serial Number

WARNING: This page does not describe the selected car, but rather 7 other vehicles, including the 2017 Honda Odyssey, 2016 Honda Odyssey, 2015 Honda Odyssey, 2014 Honda Odyssey, and 2013 Honda Odyssey. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: This procedure can only be done after the power has been disconnected and reconnected to the audio unit, and the audio unit displays CODE when the audio unit is turned on.

Turn the ignition switch to ON (II).
Make sure the audio system is turned off.
Press and hold the preset No. 1 and No. 6 buttons.
While holding the buttons, push the VOLUME/POWER knob.
Release the buttons, and the self-diagnosis begins.

Fig 1: Locating Preset No. 1, No. 6 Buttons And Volume/Power Knob
Courtesy of AMERICAN HONDA MOTOR CO., INC.
The display shows an 8-digit serial number. For example S/N 12345678.
Use all 8 numbers as the serial number when using the Interactive Network (iN) to retrieve the 5-digit anti-theft code.
To end the self-diagnostic function, turn the audio system off, or turn the ignition switch to LOCK (0).