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:
Precaution
1. Check that the battery cables are connected to the correct terminals.
2. Disconnect the battery cables when the battery is given a quick charge.
3. Do not perform tests with a high voltage insulation resistance tester.
4. Never disconnect the battery while the engine is running.
5. Check that ...
LTA (Lane Tracing Assist)
LTA functions
When driving on a road with
clear lane lines with the
dynamic radar cruise control
operating, lane lines and preceding
and surrounding vehicles
are detected using the
front camera and radar sensor,
and the steering wheel is
operated to maintain the vehicle's
lane position.
...
Inspection procedure
1 Check un–lock warning switch assy
Disconnect the key unlock warning switch connector.
check the continuity between the terminals of the key unlock
warning switch connector, as shown in the illustration
and table.
Standard:
2 Check wire harness (tvip ecu unlock warni ...


