Toyota Corolla (E120): Circuit description
This is the power source of the ecu, hence the actuators.

Wiring diagram

Other materials:
Seat belt pretensioners (front seats)
The pretensioners help the seat belts to quickly restrain the occupants by retracting
the seat belts when the vehicle is subjected to certain types of severe frontal
or side collision.
The pretensioners do not activate in the event of a minor frontal impact, a minor
side impact, a rear impact ...
Inspection procedure
1 Check p squib circuit(airbag sensor assy center – instrument
panel passenger airbag assy)
Disconnect the negative (–) terminal cable from the battery,
and wait at least for 90 seconds.
disconnect the connectors between the airbag sensor
assy center and the instrument panel ...
Circuit description
When the ignition switch is turned on, battery positive voltage is applied to
the coilwhich closes the contacts
of the efi main relay (marked: efi) and supplies power to terminal +b of the ecm.
This signal causes current to flow to the coil, closing the contacts of the efi
relay and supplyin ...


