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

Inspection procedure

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    Key information
    Keys The following keys are provided with the vehicle. ►  Vehicles without a smart key system (type A) 1 Keys 2 Key number plate ► Vehicles without a smart key system (type B) 1 Keys Operating the wireless remote control function 2 Key number plate ► Vehicles ...

    Circuit description
    The purpose of this circuit is to prevent the engine from stalling while driving in lock–up condition, when brakes are suddenly applied. When the brake pedal is depressed, this switch sends a signals to the ecm. Then the ecm cancels the operation of the lock–up clutch while braking is i ...

    How to proceed with troubleshooting
    Hint: carry out troubleshooting in accordance with the procedures on the following page. Here, only the basic procedures are shown. Details are provided in the diagnostics section, showing the most effective methods for each circuit. Confirm the troubleshooting procedures first for the releva ...