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:
Engine coolant
The coolant level is satisfactory if it is between the “F” and “L” lines on the
reservoir when the engine is cold.
1 Reservoir cap
2 “F” line
3 “L” line
If the level is on or below the “L” line, add coolant up to the “F” line.
■Coolant selection
Only use “To ...
Vehicle identification
■ Vehicle identification number
The vehicle identification number (VIN) is the legal identifier for your vehicle.
This is the primary identification number for your Toyota. It is used in registering
the ownership of your vehicle.
This number is stamped on the top left of the instrument p ...
Engine immobilizer system
The vehicle’s keys have built-in transponder chips that prevent the engine
from starting if a key has not been previously registered in the vehicle’s on-board
computer.
Never leave the keys inside the vehicle when you leave the vehicle.
Vehicles without a smart key system: The indicator li ...


