Camshaft Position ”A” Actuator Circuit - Toyota Tundra 2005 Service - Repair - Maintenance

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Table of Contents

CIRCUIT INSPECTION

CIRCUIT DESCRIPTION

The Variable Valve Timing (VVT) system includes the ECM, the Oil Control Valve (OCV) and the VVT control-

ler. 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 en-

gine operation conditions such as 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 a result, the relative position between the cam-

shaft 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 feedback con-

trol. This is how target valve timing is verified by the ECM.

Crankshaft Position Sensor

Mass Air Flow Sensor

Throttle Position Sensor

Engine Coolant Temp. Sensor

Vehicle Speed Signal

Camshaft Position Sensor

Open or short in OCV circuit

Camshaft Position "A" Actuator circuit

Camshaft Position "A" Actuator circuit

DTC Detecting Condition

ENGINE (2UZ−FE)

Target Valve Timing

Actual Valve Timing

S Open or short in OCV circuit

Camshaft Timing

Duty Control

Trouble Area