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:
Circuit description
The vapor pressure sensor, vsv for canister closed valve (ccv), vsv for
pressure switching valve are used
to detect abnormalities in the evaporative emission control system.
The ecm decides whether there is an abnormality in the evaporative emission
control system based on the
vapor pressur ...
Circuit description
The srs warning light is located on the combination meter.
When the srs is normal, the srs warning light lights up for approx. 6 Seconds
after the ignition switch is
turned from the lock position to on position, and then turns off automatically.
If there is a malfunction is the srs, the srs ...
Circuit description
Monitor description
The ecm commands gearshift by turning the shift solenoid valves ”on/off”.
When there is an open or short
circuit in any shift solenoid valve circuit, the ecm detects the problem and the
mil comes on. Illuminating
the mil, the ecm performs the fail–safe and turns ...


