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:
Inspection procedure
1 Check ignition or starter switch assy
Check the ignition switch, as shown in the illustration and
table.
Standard:
2 Check fuse (ecu–b)
Remove the fuse from the instrument panel j/b.
check the continuity of the fuse.
Standard: continuity
3 Check relay (m ...
Inspection procedure
1 Input signal check
See input signal check on page 05–745.
check indicator light operation when driving with vehicle
speed above 40 km/h (25 mph), and with vehicle speed
below 40 km/h (25 mph).
Ok:
vehicle speed above 40 km/h (25 mph):
indicator light blinks
vehicle speed be ...
Circuit description
The ecm compares the two waveforms of the heated oxygen sensors located
before and after the catalyst
to determine whether or not the catalyst performance has deteriorated.
Air–fuel ratio feedback compensation keeps the waveform of the heated oxygen
sensor in front of the catalyst
alterna ...


