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 Perform active test by hand–held tester(operation of circuit
opening relay)
Connect the hand–held tester to the dlc3.
turn the ignition switch on and push the hand–held tester main
switch on.
select the item ”diagnosis / enhanced obd ii / active ...
Power steering
Preparation
Sst
Recomended tools
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Lubricant
Ssm
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Automatic transmission / trans
Preparation
Sst
Recomended tools
Equipment
Lubricant
Ssm (special service materials)
...


