Toyota Corolla (E120): Components
Other materials:
If a warning light turns on or a
warning buzzer sounds
Calmly perform the following actions if any of the warning
lights comes on or flashes. If a light comes on or flashes, but
then goes off, this does not necessarily indicate a malfunction
in the system. However, if this continues to occur, have the
vehicle inspected by your Toyota dealer.
Actions to ...
Evap monitor (vacuum pressure monitor)
Notice:
a cold soak must be performed prior to conducting the drive pattern to complete
the internal pressure
readiness monitor.
Cold soak 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.
...
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 ...