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
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 malfunction thresholds
Component operating ra
Wiring diagram
Circuit description
When the brake pedal is depressed, the stop lamp switch assy sends a signal
to the cruise control ecu assy.
When the cruise control ecu assy receives this signal, it cancels the cruise
control.
A fail–safe function is provided so that cancel functions normally, even if
there is a malfunc ...
Changing the engine switch positions
1 “LOCK”
The steering wheel is locked and the key can be removed. (Vehicles with an automatic
transmission or continuously variable transmission: The key can be removed only
when the shift lever is in P.) 2 “ACC”
Some electrical components such as the audio system can be used.
3 “ON”
All ele ...
Circuit description
The purpose of this circuit is to prevent the engine from stalling while
driving in lock–up condition, when
brakes are suddenly applied.
When the brake pedal is depressed, this switch sends a signals to the ecm. Then
the ecm cancels the operation
of the lock–up clutch while braking is in pr ...