Ducati ST4S ABS Owner's Manual page 13

8) Digital display.
Offers four functions (see page 14).
9) Orange light.
Comes on and flashes when the motorcycle is stopped
(Immobilizer on) it is also used for immobilizer diagnosis.
Note
When the Immobizer has been activated, this light
keeps flashing for 24 hours and then goes out.The
Immobilizer is still working.
10) Orange light .
Turns on for a few seconds when the key is turned to ON
(CHECK) and then goes out; ABS on.
Turns on and flashes when the ABS system has been
turned off using the button incorporated in the LH switch
(see page 19).
Important
When the ABS light stays on, it means the ABS is
not working. This will not affect the operation of the
regular braking system. However, contact a Dealer or
Authorized Workshop. A possible cause is insufficient
battery voltage and it is a good rule to charge the battery.
Another possible cause is a fault in the system.
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