Toyota Corolla (E120) 2002–2008 Repair Manual / Diagnostics / Sfi system / Camshaft position ”a” actuator
circuit / Circuit description
Toyota Corolla (E120): 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 ”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
Other materials:
Circuit description
The d squib circuit consists of the airbag sensor assy center, spiral cable
sub–assy and horn button assy.
It causes the srs to deploy when the srs deployment conditions are satisfied.
Dtc b1180/17 is recorded when a short is detected in the d squib circuit (2nd
step).
Wiring diagra ...
How to proceed with troubleshooting
1 Vehicle brought to workshop
2 Customer problem analysis
3 Check and clear dtcs and freeze frame data
4 Problem symptom confirmation
Symptom does not occur: go to
step 5
Symptom occurs: go to step 6
5 Symptom simulation
6 Dtc check
There is no
output: go to step 7
There is outp ...
Selecting, fast-forwarding and reversing tracks/files/songs
■ Selecting a track/file/song
Press the “∧” or “∨” button on “SEEK/TRACK” or turn the “TUNE/ SCROLL” knob
to select the desired track/file/song number.
To fast-forward or reverse, press and hold the “∧” or “∨” button on “SEEK/TRACK”.
...