Maruti Suzuki India — Maruti wagon-r vxi model

Address:

831004

Power strring not funcitoning like a power steering. Its functioning like manual steering. I have visited three time to local maruti service centre. Engineers tried to resolve but after running some kilometer it becomes just like manual steering.
Vehicle no: jh05az 7878
Local service engineers tried to resolve three time but they could not resolve it permanently.
After some kilometer running it becomes again like manual steering
Kindly help me to resolve the issue i am suffering since the beginning of purchase of this car.