Toyota 2006 Yaris Owner's Manual page 124

05 11.10
If the indicator or buzzer comes on...
(n)
Key reminder
(o)
buzzer
Light reminder
(p)
buzzer
116
Stop and check.
Remove key.
Turn off lights.
2006 YARIS HATCHBACK from Aug. '05 Prod. (OM52703U)
Do this.