System Description: VTEC: Notes
- This system improves fuel efficiency and reduces exhaust emissions at all levels of engine speed, vehicle speed, and engine load.
- The VTEC system changes the cam profile to correspond to engine speed. It maximizes torque at low engine speed and output at high engine speed.
- The low lift cam is used at low engine speeds, and the high lift cam is used at high engine speeds.
- The rocker arm oil control solenoid switches both intake rocker arms of the VTEC system on and off; the solenoid is controlled by the ECM/PCM.
- The rocker arm oil pressure switch detects VTEC system oil pressure and sends this information to the ECM/PCM.
ROCKER ARM OIL PRESSURE SWITCH POSITION TABLE
| ENGINE SPEED | ROCKER ARM OIL CONTROL SOLENOID | ROCKER ARM OIL PRESSURE SWITCH | INTAKE VALVE LIFT |
|---|---|---|---|
| LOW | OFF | ON | LOW |
| HIGH | ON | OFF | HIGH |