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:
If you think something is wrong
If you notice any of the following symptoms, your vehicle probably needs adjustment
or repair. Contact your Toyota dealer as soon as possible.
Visible symptoms
● Fluid leaks under the vehicle.
(Water dripping from the air conditioning after use is normal.)
● Flat-looking tires or u ...
Switches
Instrument panel light control dial
Automatic High Beam switch
Heated steering wheel switch*
Windshield wiper de-icer switch*
Outside rear view mirror switch
Door lock switches
Power window switches
Window lock switch
*: If equipped
Meter control switches
Paddle shift switches*1
C ...
How to use this manual
General information
1. General description
This manual is made in accordance with sae j2008.
generally, repair operations can be separated in the following 3
main processes:
Diagnosis
Removing/installing, replacing, disassembling/reassembling,
checking and adju ...


