This function indicates if "lap" function (lap number) is active.
When "lap" is not lit up, this means that the function has been switched off.
The "lap" function can be activated using the "lap" function of the setting menu.

Riding mode set indication
Riding style function (riding style change)Key-on/key-off using the red key on the handlebar with the passive key
A key-on can be performed by pressing the red button (6) on
the handlebar in the hands free on/off position and in
the presence of the passive key (4, fig. 77).
Note
The passive key (4, fig. 77) Has a range of a few cm,
therefore the key (4, fig. 77) Must be positioned near the
antenna (2). R ...
Inspection of the gear selector drum
Use a gauge to measure the clearance between fork pin and the slot on the
selector drum.
If the service limit is exceeded, determine which part must be replaced by
comparing these dimensions with those of new
components (sect. 3 - 1.1, Gearbox).
Also check the wear on the drum support pin ...
First warning - oil service 1000 km
The first warning is activated at 1000 km (600 miles) of odometer reading.
The (red) warning is activated as a large icon for 10 seconds upon every key-on
(1) then as a small warning that
remains displayed (2) until it is reset.
...