Toyota Corolla (E120): Circuit description
The key unlock warning switch comes on when the ignition key is inserted in the key cylinder and goes off when the ignition key is removed.
Wiring diagram

Other materials:
Evap monitor (vacuum pressure monitor) (continued)
Preconditions
The monitor will not run unless:
mil is off.
Fuel level is approximately 1/2 to 3/4.
Altitude is 7800 feet (2400 m) or less.*
Engine coolant temperature (ect) is between 40°f and 95°f (4.4 °C and 35
°C).
Intake air temperature (iat) is between 40°f and 95 ...
Source voltage drop
The srs is equipped with a voltage–increase circuit (dc–dc converter) in the
airbag sensor assy center
in case the source voltage drops.
When the battery voltage drops, the voltage–increase circuit (dc–dc converter)
functions to increase the
voltage of the srs to normal voltage.
...
Inspection procedure
1 Check d squib circuit(airbag sensor assy center – horn button
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 horn button assy.
connect the ...


