Toyota Corolla (E120) 2002–2008 Repair Manual / Diagnostics / Sfi system / Mil circuit / Circuit description
Toyota Corolla (E120): Circuit description
The ignition switch provides circuit power and the ecm provides the circuit ground that illuminates the mil.
Mil operation is checked visually: it should be illuminated when the ignition is first turned on. If the mil is off all of the time or on all of the time, use the procedure below to troubleshoot it. The mil is used to indicate the ecm’s detection of a vehicle malfunction.
Follow this procedure using the hand–held tester or an obd ii scan tool to determine the cause of the problem and to check the mil.
Wiring diagram

Other materials:
Window lock switch
Press the switch to lock the passenger window switches.
Use this switch to prevent children from accidentally opening or closing a passenger
window.
■The power windows can be operated when
► Vehicles without a smart key system
The engine switch is in the “ON” position.
υ ...
Changing engine switch
modes
Modes can be changed by
pressing the engine switch with
brake pedal released. (The
mode changes each time the
switch is pressed.)
OFF*1
The emergency flashers can be
used.
ACC*2
Some electrical components such
as the audio system can be used.
"ACCESSORY" will be displayed
on the multi-info ...
Circuit description
Refer to dtc p0120
Dtc no.
Dtc detection condition
Trouble area
P0121
The following condition is met 4 times. After the vehicle speed
has exceeded 19 mph (30 km/h) once, the throttle position
sensor output value is out of normal range when the throttle
...


