Toyota Tacoma manuals

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:

How to proceed with troubleshooting
The handheld tester can be used at step 3, 4, 5, 7, 10. 1 Vehicle brought to workshop 2 Customer problem analysis 3 Connect handheld tester to dlc3 Hint: if the display indicates a communication fault in the tool, inspect dlc3. 4 Check dtc and freeze frame data Hint: record or print ...

Circuit inspection
1 Check d squib circuit(airbag sensor assy center horn button assy) Disconnect the negative () terminal cable from the battery, and wait at least for 90 seconds.  disconnect the connectors between the airbag sensor assy center and the horn button assy.  connect the nega ...

Seat belt pretensioners (front seats)
The pretensioners help the seat belts to quickly restrain the occupants by retracting the seat belts when the vehicle is subjected to certain types of severe frontal or side collision. The pretensioners do not activate in the event of a minor frontal impact, a minor side impact, a rear impact ...

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