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:
Circuit description
Refer to dtc p0115
Dtc no.
Dtc detection condition
Trouble area
P0125
If the engine coolant temperature (ect) was less than –6.6 °C
(20 °F) when starting the engine, and 20 minutes after the engine
start, the ect sensor still indicates below 20 °C (68 ...
Key confinement prevention function does not work
properly (unlock warning switch circuit)
Circuit description
The unlock warning switch turns on when the key is inserted in the ignition
key cylinder and the door courtesy
switch turns on when the driver’s door is opened, and the integration relay
monitors both switches conditions.
According to these switches conditions, the int ...
Front passenger occupant classification
system
Your vehicle is equipped with a front passenger occupant
classification system. This system detects the conditions of
the front passenger seat and activates or deactivates the front
passenger airbag and seat cushion airbag in the front passenger
side.
System components
SRS warning light
Front pa ...


