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:
Replacement
1. Remove engine under cover rh
2. Remove fan and generator v belt
3. Remove generator assy
Disconnect the wire clamp from the wire clip on the rectifire
end frame.
remove the rubber cap and nut, and disconnect the alternator
wire.
disconnect the alternator connecto ...
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:
...
Inspection procedure
1 Check courtesy lamp switch
Check the courtesy switch, as shown in the illustration
and table.
Standard:
2 Check wire harness (integration relay door courtesy sw)
Disconnect the integration relay and door courtesy connectors.
check the continuity between th ...


