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
Hand–held tester:
1 Check operation of stop light
Check if the stop lights go on and off normally when the brake pedal is
depressed and released.
2 Inspect stop light switch assy
Check the resistance between the terminals when the
switch is turned on and off.
Standard:
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On–vehicle inspection
1. Inspect speedometer
check the operation.
Using a speedometer tester, inspect the speedometer fro allowable
indication error and check
the operation of the odometer.
Reference:
Notice:
tire wear and tire over or under inflation will increase the indication error.
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Brake
Service data
Torque specification
Parking brake
Service data
Torque specification
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