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:
Clock assy
Replacement
1. Remove console panel upper
2. Remove heater control knob
3. Remove instrument cluster finish panel
4. Remove clock assy
Using a screwdriver, disengage the 4 claws, remove the
clock as shown in the illustration.
Hint:
tape the screwdriver tip before use. ...
Inspection procedure
1 Inspect terminal voltage(idl)
Remove the cruise control ecu assy with connector still
connected.
disconnect the ecm connector.
turn the ignition switch to on.
measure voltage between terminal 13 (idl) of cruise control
ecu assy connector and body ground when the ...
Circuit description
When a misfire occurs in the engine, hydrocarbons (hc) enter the exhaust in
high concentrations. If this hc
concentration is high enough, there could be an increase in exhaust emissions
levels. High concentrations
of hc passing through the catalyst also cause to temperature of the catalyst to ...


