Subaru BRZ 2018 Owner's Manual page 267

Within 5 seconds after the indicator lights turn off, release
STEP 5
. Then, press the switch again within 2 seconds of
releasing it.
The hill start assist ON indicator will illuminate and then turn off.
Turn the engine switch to the "LOCK" position (vehicles
STEP 6
without a keyless access with push button start system) or
turn the push-button ignition switch off (vehicles with a key-
less access with push button start system). Then, restart
the engine and check that the hill start assist ON indicator
is illuminated.
The hill start assist system is enabled when the indicator is illumi-
nated.
To disable the hill start assist system, perform the above
through again.
STEP 6
2-4. Using other driving systems
2
STEP 1
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