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 roof headlining assy
2. Remove sliding roof glass sub–assy
using a torx wrench (t25), remove the 4 screws the sliding roof
glass.
pull the glass upward to remove it.
3. Remove sliding roof weatherstrip
4. Remove sliding roof drive gear sub–assy
Notice:
...
License plate lamp assy
Replacement
1. Remove luggage compartment lock cylinder & key set
2. Remove luggage compartment door garnish outside
3. Remove license plate lamp assy
Pull the license plate light assy to the side of vehicle as
shown in the illustration and release the claw.
disconnect the c ...
Oxygen / af sensor heater monitor
Preconditions
The monitor will not run unless:
mil is off
drive pattern
connect the obd ii scan tool to the dlc3 to check monitor status
and preconditions.
Start the engine and allow it to idle for 9 minutes.
Drive the vehicle at 25 mph (40 km ...


