2004 BMW 525i Active Steering problem

The Active Steering system uses a Papst brushless dc motor to rotate the cage (ring gear) containing the planet gears a planetary gearbox at the bottom of the steering column. The motor effectively changes the steering ratio by increasing or decreasing the amount of gearbox output rotation relative to changes in the steering-wheel angle input. The resulting ratio depends on the speed of the car. For instance, a low 10:1 ratio gives high maneuverability for parking in tight spaces, with less than two turns of the steering wheel, lock to lock. To track straight at highway speeds, where even a small steering input can produce a quick sideways acceleration, the electric drive boosts the ratio to 20:1. Cars without Active Steering typically have ratios halfway between (specifically 14.1:1 for the BMW).
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Now, if your active steering does not work , the car reverses back to power steering and the ratio is 15.1:1 so the car can be driven but the "active steering " is not working and still needs to be fixed.
It the unit needs to be replaced and your car is not under warranty, the repair cost may reach 5000 dollars.