Toyota Corolla (E120): Circuit description

The variable valve timing (vvt) system includes the ecm, the oil control valve (ocv) and the vvt controller.

The ecm sends a target ”duty–cycle” control signal to the ocv. This control signal, applied to the ocv, regulates the oil pressure supplied to the vvt controller. Camshaft timing control is performed based on engine operation conditions such as the intake air volume, throttle position and engine coolant temperature.

The ecm controls the ocv, based on the signals output from the sensors. The vvt controller regulates the intake camshaft angle using oil pressure through the ocv. As result, the relative position between the camshaft and the crankshaft is optimized, and the engine torque improves, fuel economy improves, and exhaust emissions decrease under overall driving conditions. Also, the ecm detects the actual valve timing using signals from the camshaft position sensor and the crankshaft position sensor, and performs the feedback control. This is how target valve timing is verified by the ecm.

Monitor description

Monitor description

After the ecm sends the ”target” duty–cycle signal to the ocv, the ecm monitors the ocv current to establish an ”actual” duty–cycle. The ecm detects a malfunction and sets a dtc when the actual duty–cycle ratio varies from the target duty–cycle ratio.

Monitor strategy

Typical enabling conditions

Typical enabling conditions

Typical malfunction thresholds

Typical malfunction thresholds

Component operating ra

Component operating ra

Wiring diagram

Wiring diagram

Inspection procedure

    Share this page:

    Other materials:

    Stopping
    ► Automatic transmission or continuously variable transmission 1 With the shift lever in D, depress the brake pedal. 2 If necessary, set the parking brake. If the vehicle is to be stopped for an extended period of time, shift the shift lever to P or N. (, 174, 176) ►  Manual ...

    Circuit description
    Refer to dtc p0115 Dtc no. Dtc detection condition Trouble area P0125 If the engine coolant temperature (ect) was less than –6.6 °C (20 °F) when starting the engine, and 20 minutes after the engine start, the ect sensor still indicates below 20 °C (68 ...

    Using the steering wheel switches
    The steering wheel switches can be used to operate a connected cellular phone or portable digital audio player (portable player). Operating a Bluetooth® phone using the steering wheel switches 1 Volume The voice guidance volume cannot be adjusted using these buttons. 2 Off-hook switch Turns ...