Hill start assist warning light (MT models – if equipped)/Hill start assist OFF indicator light (STI)
Subaru Impreza / Subaru Impreza Owners Manual / Instruments and controls / Warning and indicator lights / Hill start assist warning light (MT models – if equipped)/Hill start assist
OFF indicator light (STI)

See also:
System monitors
A diagnostic system continually monitors the readiness of the seatbelt pretensioner while the vehicle is being driven. The seatbelt pretensioners share the control module with the SRS airbag system.
...
Non-turbo models
The non-turbo engine is designed to operate using unleaded gasoline with an octane
rating of 87 AKI or higher. ...
Type A audio set (if equipped)
The audio set will operate only when the ignition switch is in the “Acc” or “ON”
position.
● Power and sound controls: refer to page 5-6
● Radio operation: refer to page 5-9
● ...
