The steering wheel's electromechanical amplifier

The steering follows the design of the previous model: electromechanical power steering, a mechanically adjustable steering column and a wide choice of steering wheels. (as on the previous model: power steering, adjustable column, choice of steering wheels)

The column can be adjusted steplessly by sixty millimeters for reach and by fifty for height. (column: 60 mm reach · 50 mm height, stepless)

The power steering works as before: a second pinion, driven by the electric motor, helps move the rack. (second pinion — driven by electric motor V187)

The torque sensor on the steering column shaft measures the effort that the driver applies to the steering wheel. (G269 — steering torque sensor)

From this torque, the vehicle speed, the steering angle and the steering speed, the control unit calculates how much assistance to add. (J500: torque, vehicle speed, steering angle and steering speed)

The main difference is a synchronous electric motor instead of an asynchronous one: together with the new housing shape, the mechanism became two and a half kilograms lighter. (synchronous motor instead of asynchronous · mechanism −2.5 kg)

The rotor position is monitored by a sensor in the motor, and a temperature sensor in the control unit monitors the output stage: if it overheats, the assistance is gradually reduced. (G28 — rotor position · overheating — assistance reduced)

Since the power steering can turn the steering wheel by itself, park assist and a steering recommendation when braking with different grip under the left and right wheels are based on it. (park assist · DSR — steering recommendation)

The assistance depends on vehicle speed, and the power steering compensates for crosswinds and road camber by itself. (speed-dependent assistance · crosswind and camber compensation)

Five degrees before the end stop, the power steering builds up a counter-torque so that the steering wheel does not hit the stop when turned quickly. (5° before the end stop — counter-torque)

Later, a steering gear with a variable ratio will be offered with the sports suspension — thanks to a special tooth shape of the pinion and rack. (variable ratio — special tooth shape)

With it, you have to turn the steering wheel noticeably less at large steering angles, such as when parking. (at large angles — noticeably less steering wheel travel)

With the mode selection system, the driver changes the steering characteristic from comfortable to sporty — all characteristics are stored in the power steering control unit. (characteristics — in J500: from comfortable to sporty)

The yellow warning lamp lights up if the steering angle sensor is not calibrated: the assistance drops by about sixty percent, and after calibration the lamp goes out. (yellow: G85 not calibrated — assistance ≈ −60 %)

The yellow lamp together with a message on the display indicates a fault: you can still drive to a workshop, but with reduced assistance. (yellow + message: fault, reduced assistance)

The red lamp must go out a few seconds after the ignition is switched on; if it stays on, the power steering is not working and you must not continue driving. (red stays on — power steering inactive, do not drive)

Individual parts are not replaced: in the event of a fault, the complete steering gear is replaced. (no individual parts — complete steering gear replaced)

A new control unit is coded online, and before that the steering angle sensor is calibrated — the end stop positions are stored during calibration. (online coding · G85 calibration before it)

The calibration activates the power steering characteristic for the particular vehicle — according to the front axle load or the vehicle weight. (characteristic — by axle load or vehicle weight)