What is OEM number 4G0909144Q and which part does it identify?

OEM number 4G0909144Q identifies the steering rack for the Audi A8 D4 (4H2, 4H8, 4HC, 4HL), and is also fitted across related Audi models built on the same platform. The part is an electric power steering rack, also marketed as a power steering rack and pinion assembly or steering gear box. The component is built for left-hand-drive vehicles only, and a separate right-hand-drive equivalent is required for right-hand-drive markets. It is also known as an electric power steering (EPS) rack, where EPS refers to the electronic motor-assisted steering mechanism. Cross-reference numbers associated with this part include 4G0909144K, 4G0909144H, 4G0909144G, and 4G0909144T. OEM number 4G0909144Q may fit additional vehicle models not listed here, so always verify against the OEM number on your existing part.

Does OEM number 4G0909144Q fit my vehicle?

OEM number 4G0909144Q fits the Audi A8 D4, built between 2015 and 2018, and specifically confirmed on the S8 plus quattro variant with the 4.0-litre V8 DDTA petrol engine producing 445 kW (605 hp). The same part number is also associated with the Audi A6 C7, A7, A8, and S8 models as a power steering rack and gear box.

The most important constraint governing fitment is steering side: this steering rack is built for left-hand-drive vehicles only. Multiple listings confirm the part is supplied for left-hand drive vehicles, with the set fitting only left-hand drive applications. A separate right-hand-drive equivalent exists for UK-market vehicles, though its exact OEM number could not be confirmed from available sourcing and should be verified against the number printed on the existing part before ordering. The Audi A6 C7 and A7 4G applications using this cross-reference are dated broadly from 2012 to 2018.

Audi A8 D4 (4H2, 4H8, 4HC, 4HL), S8 plus quattro, DDTA 4.0-litre V8 petrol, 445 kW (605 hp), left-hand drive, built 2015 to 2018.

Cross-reference data also associates OEM number 4G0909144Q with the Audi A6 C7, A7 4G, and standard S8 quattro models, but these carry different engine outputs and body styles to the A8 D4 S8 plus quattro confirmed above. Verify the printed number on your existing part before ordering if fitting a vehicle outside the A8 D4 generation.

OEM number 4G0909144Q may fit additional vehicle models not listed here. Always verify by checking the OEM number printed on your existing part.

Fits: Audi A8 D4 (4H2, 4H8, 4HC, 4HL), S8 plus quattro, 4.0-litre V8 petrol (DDTA engine code), 445 kW / 605 hp, left-hand drive only, 2015 to 2018
Does not fit: right-hand drive vehicles

How is OEM number 4G0909144Q installed?

Fitting this steering rack is a coded module procedure combined with a mechanical steering assembly replacement. The electric power steering (EPS) unit requires a VAG-compatible diagnostic tool, such as VCDS or ODIS, to code the new control module to the vehicle after installation. Without coding, the steering control unit will not communicate correctly with the vehicle network, and a steering-related warning light will remain illuminated on the instrument cluster. Because the rack is a steering component, the vehicle also requires a four-wheel alignment after fitting to restore correct wheel geometry.

1. Confirm the replacement rack matches the drive side (left-hand drive) of the vehicle before fitting.
2. Disconnect the battery before removing the original steering rack.
3. Fit and torque the new steering rack according to the vehicle manufacturer's specification.
4. Code the electric power steering control module using a VAG-compatible diagnostic tool.
5. Carry out a four-wheel alignment before returning the vehicle to the road.

When should OEM number 4G0909144Q be replaced?

Replacement triggers

• Steering wheel feels loose, notchy, or has increased free play before the wheels respond.
• Whirring, grinding, or clicking noise from the steering rack area during turns.
• Steering assistance warning light illuminated on the dashboard.
• Uneven or inconsistent steering effort at different speeds or lock angles.
• Visible fluid leakage or corrosion around the steering rack housing.
• Vehicle pulls to one side independent of tyre pressure or wheel alignment.

We used AI to help write this text. We regularly check the information - but cannot guarantee that all data is accurate.