A phaser which includes a housing and a rotor disposed to rotate relative to each other is provided. The housing has at least one cavity disposed to be divided by a vane rigidly attached to the rotor. The vane divides the cavity into a first chamber and a second chamber. The phaser further includes passages connecting the first and the second chamber, thereby facilitating the oscillation of the vane within the cavity. The phaser includes: a) a valve disposed to form at least two openings for fluid flowing between the first chamber and the second chamber and being disposed to keep at least one opening closed; and b) at least one by-pass disposed to stop or slow down the rotation between the housing and the rotor, thereby allowing a locking mechanism to lock the housing and the rotor together independent of fluid flow.