A fluid
injector is specified. The fluid
injector has a longitudinal axis (L) and comprises a valve body (6), a valve needle (12), being received in the valve body (6), being axially moveable and being operable to prevent a
fluid injection in a closing position and to permit the
fluid injection in further positions, an armature (14) being mechanically coupled to the valve needle (12) so that it is operable to displace the valve needle (12) away from the closing position, and a solenoid
assembly (30) comprising at least a first and second coil (34, 36) and being operable to magnetically actuate the armature (14) via an electrical
signal (I 1 ). A method for operating the fluid
injector comprises applying the electrical
signal (I 1 ) to the first coil (34) to generate a primary
magnetic field to move the armature (14) for displacing the valve needle (12) away from the closing position, evaluating a
voltage (U 1 ) across terminals of the first coil (34), and controlling the second coil (36) with a further electrical
signal (I 2 ) to saturate a
magnetic field in a portion of the valve body (6) which is located between the armature (14) and the solenoid
assembly (30) during evaluating the
voltage (U 1 ).