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Toyota Corolla Repair Manual: 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 dutycycle 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 dutycycle signal to the ocv, the ecm monitors the ocv current to establish an actual dutycycle. The ecm detects a malfunction and sets a dtc when the actual dutycycle ratio varies from the target dutycycle 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

Camshaft position a actuator circuit
Dtc p0010 camshaft position a actuator circuit (bank 1) ...

Inspection procedure
Hint: read freeze frame data using the handheld tester or the obd ii scan tool. Freeze frame data records the engine conditions when a malfunction is detected. When troubleshooting, it is usefu ...

Other materials:

Mass or volume air flow circuit
Dtc p0100 mass or volume air flow circuit Dtc p0102 mass or volume air flow circuit low input Dtc p0103 mass or volume air flow circuit high input Circuit description The maf (mass air flow) sensor measures the amount of air flowing through the throttle valve. The ecm uses this information ...

Inspection procedure
1 Check airbag sensor assy center connector Disconnect negative () terminal cable from the battery, and wait at least for 90 seconds.  check the connection of the airbag sensor assy center connectors. 2 Check air bag sensor assy center Sst 0984318040 Connect the negat ...

Precheck
1. Diagnosis system Release the parking brake lever.  check the warning lights. When the ignition switch is turned on, check that the abs warning light and brake warning light goes on for 3 sec. Hint: when the parking brake is applied or the level of the brake fluid is low, the ...

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