The mode changes between ACCESSORY mode and ON mode, but it does not change to OFF (LOCK) mode

WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2020 Honda Fit, 2019 Honda Fit, 2018 Honda Fit, 2017 Honda Fit, and 2016 Honda Fit. However, it is still accessible from the selected car via links, so may be relevant.

Diagnostic procedure

Check the keyless access control unit
Check the park pin switch
Check the transmission range switch
Check clutch pedal position switch

Also check for

Keyless access control unit
ATP-P line open
Transmission range switch
Park pin switch
P-PIN SW line open
Clutch pedal position switch