Subaru Impreza 2002 Service Manual page 33

Mechanical
C: A CERTAIN PHASE ANGLE IS RETAINED
When the ECM issues a signal to keep the phase angle unchanged, the oil flow control valve moves
its spool to the position at which the hydraulic pressures to/from both the chambers are blocked.
The pressures in the chambers are thus maintained, so the phase angle does not change and the
intake valves' opening and closing timings also remain unchanged.
(1) Variable valve timing controller (attached to camshaft sprocket)
(2) Vane (attached to intake camshaft)
(3) ECM
(4) Oil flow control valve
(5) Hydraulic pressure
VARIABLE VALVE TIMING SYSTEM
ME-8
NF0583