Toyota Corolla Quiz
Diagnostics

Circuit description

In this manual: Diagnostics
Introduction — 31Preparation — 32Service specifications — 19Diagnostics — 497Engine control system — 6Fuel — 13Emission control — 28Exhaust — 3Cooling — 13Lubrication — 7Ignition — 3Starting & charging — 13Front suspension — 12Rear suspension — 9Tire & wheel — 1Drive shaft / propeller shaft — 15Brake — 42Automatic transmission / trans — 47Clutch — 19Steering column — 9Power steering — 11Heater & air conditioner — 20Supplemental restraint system — 27Seat belt — 12Lighting — 18Wiper & washer — 9Audio & visual — 12Wiring — 1Communication system — 1Windshield/windowglass/mirror — 31Seat — 10Theft deterrent & door lock — 10Sliding roof/convertible — 8Engine hood/door — 12Exterior/interior trim — 20Vehicle control system — 1Cruise control — 5Maintenance — 8
~1min read

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
Toyota Corolla. Wiring diagram

Test yourself

A quick Toyota Corolla quiz: every answer comes with an explanation and a link to the manual page.