Subaru BRZ 2018 Owner's Manual page 475

Vehicles with a manual transmission
Set the parking brake.
STEP 1
Put the shift lever in neutral.
STEP 2
Turn the push-button ignition switch to "ACC" mode.
STEP 3
Push and hold the push-button ignition switch for about 15
STEP 4
seconds while depressing the brake pedal and clutch pedal
firmly.
Even if the engine can be started using the above steps, the system
may be malfunctioning. Have the vehicle checked by your SUBARU
dealer.
5-2. Steps to take in an emergency
5
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