Steering gear ASTON MARTIN DB11 16-23 KY73-3200-BC KY733200BC.R

part number KY73-3200-BC (and the remanufactured variant KY733200BC.R) identifies the Electric Power Steering (EPS) Rack and Pinion Assembly for the Aston Martin DB11 (2016–2023) and the DBS Superleggera.

This is a sophisticated, variable-ratio electric steering gear that moved the DB11 away from the hydraulic systems of the previous DB9 generation.

Technical Specifications

• Type: Electric Rack and Pinion (EPS).

• Orientation: RHD (Right-Hand Drive). (The LHD version typically carries a different prefix or suffix, such as KY53-3200-AA).

• Steering Ratio: Variable ratio, approximately 2.2 turns lock-to-lock.

• Manufacturer: Primarily supplied by ZF.

• Operating Mode: Electric motor mounted directly to the rack (Rack-EPS) to provide high-torque assistance without robbing engine power.

Key Identification & Suffixes

The part number suffix indicates the revision level:

• KY73-3200-BC: The standard OEM production part.

• KY733200BC.R: The “.R” suffix designates a Remanufactured/Refurbished unit. These are common in the secondary market and are usually professionally rebuilt with new seals and updated electronic controllers to meet original specs at a lower cost (~£700–£900 vs. £7,000+ for new).

Common Issues & Diagnostics

If you are sourcing this part due to a steering fault, check for these common DB11 steering symptoms:

1. “Power Steering Reduced” Warning: Often caused by a voltage drop or a communication error between the car’s ECU and the steering rack’s internal control module.

2. Notchy Feeling: Since this is an electric rack, a “notchy” or “lumpy” feel often points to a failure in the internal ball-screw mechanism or a bearing issue within the electric motor.

3. Water Ingress: The electric motor and its harness connector are located low in the chassis. If the protective bellows (boots) are torn, water can enter the rack and short out the electronics.

Important Installation Note

The DB11 steering rack is a “coded” component.

• Software Pairing: After physical installation, the new (or remanufactured) rack must be programmed to the car using the Aston Martin Diagnostic System (AMDS).

• SAS Calibration: You must perform a Steering Angle Sensor (SAS) calibration to ensure the Traction Control and Torque Vectoring systems function correctly. The car will likely throw an ESP/DSC error until this is completed.