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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    Pre–check
    1. Diagnosis check Starting diagnosis mode (service check mode)  turn off the audio system and turn the ig switch to acc. While pressing the preset switches ”1” and ”6” at the same time, press ”cd” 3 times. Reference: beep sound is given 3 times and the sys ...

    Inspection
    1. Cooler thermistor no.1 Check resistance between terminals 1 and 2 of cooler thermistor no. 1 At each temperature, as shown in the chart. Resistance: If resistance value is not as specified, replace the sensor. 2. Cooler and accessory assy Inspect blower switch contin ...

    Inspection procedure
    1 Inspect fuse(ecu–ig fuse) Remove ecu–ig fuse from the instrument panel j/b.  check continuity of ecu–ig fuse. Ok: continuity 2 Inspect battery Ok: voltage: 10 – 14 v 3 Inspect skid control ecu connector(ig1 terminal voltage) In case of using hand–held te ...