Heavy or failed power steering: causes, recalls and affected cars

Steering that goes heavy, whines or loses its assistance while driving is a safety issue: at low speed, the car becomes hard to manoeuvre. The causes differ between hydraulic steering (pump, fluid, leaks) and electric steering (motor, control unit, wiring).

Hydraulic steering: leaks and pump

On hydraulic steering, a fluid leak or a tired pump makes the steering heavy. BMW X3s built up to 2005 are known for power steering leaks (Fiches-auto), and X5s and X6s from the first quarter of 2012 were recalled for a rack that could leak (Fiches-auto, X5; Fiches-auto, X6). A pump that gets noisy at idle is an early warning (Fiches-auto, BMW 7 Series).

Electric steering: control unit, rack, wiring

• The rack: one of the major weak points of the BMW X3 F25; it quickly develops play, sometimes with a failure of the steering control unit (Fiches-auto; CarVerif).
• The control unit: a campaign covered BMW 1 Series built from 18 July 2011 to 9 June 2016 for a possible soldering defect in the power steering control unit (Fiches-auto); on the BMW X4, a fault in this unit can cause loss of assistance while driving (Fiches-auto).
• Wiring: on the Alfa Romeo Tonale, faulty wiring can cut the lights, hazard warning, power steering and brake assistance (Fiches-auto); an Alfa Romeo MiTo owner describes electric assistance that can suddenly cut out (Fiches-auto).

Even recent cars are affected: Tesla recalled tens of thousands of Model S and Model X cars for their power steering (Caradisiac).

Before buying a used car

Turn the wheel lock to lock when stationary and when manoeuvring: the steering should stay light, with no noise or jerking, and no warning light should come on. Check with the VIN that steering recalls have been done; any loss of assistance during the test drive is a reason to walk away (CarVerif, Renault Twingo II).