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:
Inspection procedure
1 Check front airbag sensor (lh) circuit (to b+)(airbag sensor assy
center – airbag sensor front lh)
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 airbag ...
How to proceed with troubleshooting
1 Vehicle brought in
2 Customer problem analysis check and symptom check
3 Problem symptoms table
Without applicable symptoms, proceed to ”a”
with applicable symptoms, proceed to ”b”
4 Perform troubleshooting in the following method, depending on
malfunction symptom ...
Rear seats
► Type A
1 Up
Pull the head restraints up.
2 Down
Push the head restraint down while pressing the lock release button.
► Type B
1 Up
Pull the head restraints up.
2 Down
Push the head restraint down while pressing the lock release button.
■Removing the head restraints ...


