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:
Overhaul
1. Remove w/head taper screw plug no.2
Using a socket hexagon wench 10, remove the taper
screw plug and gasket.
2. Remove valve lifter
Remove the valve lifters from the cylinder head.
3. Remove valve
Place the cylinder head on wooden blocks.
using sst, compres ...
Circuit description
When the ignition switch is turned on, battery positive voltage is applied to
the coilwhich closes the contacts
of the efi main relay (marked: efi) and supplies power to terminal +b of the ecm.
This signal causes current to flow to the coil, closing the contacts of the efi
relay and supplyin ...
If the vehicle becomes stuck
Carry out the following procedures if the tires spin or the vehicle becomes
stuck in mud, dirt or snow:
1 Stop the engine. Set the parking brake and shift the shift lever to P (automatic
transmission or continuously variable transmission) or N (manual transmission).
2 Remove the mud, snow or s ...


