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:
Meter display
■ Locations of gauges and meters
Engine coolant temperature gauge
Displays the engine coolant temperature
Outside temperature
Displays the outside temperature within the range of -40ºF (-40ºC) to 140ºF
(60ºC)
Analog speedometer/Tachometer
This setting can be changed on the setting scr ...
On–vehicle inspection
1. Inspection throttle body idle speed control valve assy
Notice:
it is impossible to check the resister value and the operation
of isc valve by itself, because the isc valve
has an ic circuit inside it, which transforms the duty
signal from the ecm to the derive signal.
After check ...
Inspection
1. Charcoal canister assy
Visually check the charcoal canister for cracks or damage.
Inspect the charcoal canister operation.
Plug the vent port with the cap.
While holding the purge port closed, blow air (1.76
Kpa, 18 gf/cm2, 0.26 Psi) into the evap port and
...


