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:
Battery
Check the battery as follows.
■ Battery exterior
Make sure that the battery terminals are not corroded and that there are no
loose connections, cracks, or loose clamps.
1 Terminals
2 Hold-down clamp
■Before recharging
When recharging, the battery produces hydrogen gas which is ...
Circuit description
Hint:
these dtcs indicate a malfunction related to the primary circuit.
If dtc p0351 is displayed, check the no.1 Ignition coil with igniter
circuit.
If dtc p0352 is displayed, check the no.2 Ignition coil with igniter
circuit.
If dtc p0353 is displayed, check the no.3 Ignition coil ...
On–vehicle inspection
1. Inspect cooling system for leaks
Caution:
to avoid the danger of being burned, do not remove the radiator
cap while the engine and radiator are still hot, as fluid
and steam can be blown out under pressure.
fill the radiator with coolant and attach a radiator cap tester.
  ...


