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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:

Circuit description
Refer to dtcs p0100 Dtc no. Dtc detection condition Trouble area P0101 After engine is warmed up, conditions (a) to (d) continue for more than 10 seconds (2 trip detection logic):  engine speed less than 900 rpm  throttle valve fully closed &nbs ...

Engine coolant
The coolant level is satisfactory if it is between the F and L lines on the reservoir when the engine is cold. 1 Reservoir cap 2 F line 3 L line If the level is on or below the L line, add coolant up to the F line. ■Coolant selection Only use Toyota Super Long Life Coola ...

Ecu power source circuit
Circuit description This circuit provides power to operate the tvip ecu. Wiring diagram Inspection procedure 1 Check fuse (ecub) Remove the fuse from the instrument panel j/b.  check the continuity of the fuse. Standard: continuity 2 Check tvip ecu Disconnect th ...

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