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:
Symptom simulation
Hint:
the most difficult case in troubleshooting is when no symptoms occurs. In such
cases, a thorough customer
problem analysis must be carried out. Then the same or similar conditions and
environment in which the
problem occurred in the customer’s vehicle should be simulated. No matter ho ...
Monitor description
Dtc p0451, p0452 or p0453 is recorded by the ecm when the vapor pressure
sensor malfunctions.
P0451
The ecm senses pressure in the fuel tank using the vapor pressure sensor. The
ecm supplies the sensor
with a regulated 5 v reference–voltage and the sensor returns a signal voltage
betwee ...
On–vehicle inspection
1. Inspect wireless door lock control functions
Hint:
the switch described in this text is a switch for transmitting
signals (lock switch, unlock switch
and panic switch) which is built into the door control transmitter.
All the functions listed below must be checked in the remote contro ...


