Toyota Corolla (E120): Circuit description

When the ignition switch is turned on, battery positive voltage is applied to the coilwhich closes the contacts of the efi main relay (marked: efi) and supplies power to terminal +b of the ecm.

This signal causes current to flow to the coil, closing the contacts of the efi relay and supplying power to terminal +b of the ecm.

If the ignition switch is turned off, the ecm continues to switch on the efi relay for a maximum of 2 seconds for the initial setting of the isc valve.

Wiring diagram

Inspection procedure

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    Inspection
    1. Thermostat Hint: the thermostat is numbered with the valve opening temperature. Immerse the thermostat in water and gradually heat the water.  check the valve opening temperature. Valve opening temperature: 80 to 84 c (176 to 183 f) Hint: if the valve opening temperatur ...

    Other functions
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    Outside temperature display
    The temperature display shows temperatures within the range of -40°F (-40°C) to 122°F (50°C). ► Type A ► Type B ► Type C ► Type D ■The outside temperature is displayed when ►Vehicles without a smart key system The engine switch is in the “ON ...