Audi A5 (2011 – 2018) Electric Power Steering Rack

The Audi A5 (B8, 2011–2018) — whether coupe, Sportback or Cabriolet — is steered by an electromechanical power steering rack, with the assist motor and control module integrated into the rack itself and no hydraulic pump involved. Across all three body styles the fault is the same: the electronics inside the rack fail while the mechanical rack and pinion stay sound. We repair the A5’s original rack and steering ECU at component level and return the same unit, so the car keeps its original coding and the weak points are reinforced against a repeat failure.

How the fault presents

The clearest sign is the red “Steering defective! Do not drive vehicle!” message on the cluster. It means exactly that — do not carry on driving the A5 once it is displayed.

• Red “Steering defective! Do not drive vehicle!” warning on the cluster
• Heavy, unassisted steering, most noticeable when parking or manoeuvring
• Steering that no longer self-centres after a turn
• The warning appearing intermittently before becoming permanent
• On some cars, the A5 refusing to start with the warning active

The fault codes

Scanning an affected A5 rack, two codes come up repeatedly:

• C10AD29 — Motor Position Sensor
• B200049 — Internal Control Module Error

Both are internal to the rack’s own electronics rather than the tie rods, column or wiring — which is why a dealer scan usually leads straight to a full rack replacement.

Where the fault lies

The failure points sit inside the rack’s integrated steering ECU. The motor position sensor (C10AD29) stops reporting the assist motor’s position reliably, so the module shuts assistance down rather than trust unreliable data. Separately, the control module’s electronics fail internally (B200049). Years of heat, vibration and moisture take their toll on the sensor and control board — not the mechanical rack and pinion, which are typically still in good order.

Repairing the A5 rack rather than scrapping it

Because the fault is electronic, your A5’s original rack can be repaired at component level rather than replaced with a complete assembly — whichever body style you have. Ours is a mail-in repair-and-return service: you send in the failing rack and steering ECU, our engineers rebuild it in a cleanroom-standard, ESD-safe workshop with circuit-level repair to the sensor and control module, and we return your own unit repaired to meet or exceed OE specification. The known weak points are reinforced, most remanufactured parts carry a lifetime, unlimited-mileage warranty, and your original coding is preserved. Because the identical rack is fitted across the coupe, Sportback and Cabriolet, the repair itself is the same whichever A5 you own, and returning your own unit removes any guesswork over matching a replacement to your exact build.

Once checkout is done, print the repair form, fill in your details and the symptoms, and pack it in the box with your A5 rack — or send it to us in advance. With it in the box, your unit is ready to go straight onto the bench. If you’d first like to check the rack is the exact part your car needs, our full electric power steering repair service covers the related columns and ECUs.