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:
Electronic control
Removal and installation of battery terminal
before performing electrical work, disconnect the
battery negative (–) terminal cable beforehand so
as to prevent burnt–out damage by short.
When disconnecting and installing the terminal
cable, turn the ignition switch an ...
Headlight switch
The headlights can be operated
manually or automatically.
Operating instructions
Operating theswitch
turns on the lights as follows:
For the U.S.A.
The headlights, daytime
running lights and
all the lights listed below turn
on and off automatically.
The side marker,
parking,
LED ac ...
General information
There are many ecu controlled systems used in the corolla. In general, ecu
controlled system are considered
to be very intricate and require a high level of technical knowledge and expert
skill to troubleshoot.
The fact is, however, that if you proceed by inspecting the circuits one by one, ...


