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:
Have the malfunction repaired immediately. (vehicles with a smart key system)
After taking the specified steps to correct the suspected problem, check that
the warning message and light go off.
■Warning buzzer ...
Inspection procedure
1 Check d squib circuit(airbag sensor assy center – horn button
assy)
Disconnect the negative (–) terminal cable from the battery,
and wait at least for 90 seconds.
disconnect the connectors between the airbag sensor
assy center and the horn button assy.
release the airbag activ ...
Speedometer sensor (atm)
Replacement
1. Remove air cleaner case
2. Remove air cleaner hose no.1
3. Remove speedometer sensor
disconnect the connector.
remove the bolt and speedometer sensor assembly.
remove the clip and driven gear from the speedometer
sensor.
4. Install speedometer sensor
...


