BMW Z4 G29 TOYOTA SUPRA MK5 steering gear 225A40325-01 5B38FB6

part numbers you’ve listed, 225A40325-01 and 5B38FB6, correspond to the Electric Power Steering (EPS) Rack used in the BMW Z4 (G29) and the Toyota Supra MK5 (A90/A91).

Because these two vehicles share the same chassis and steering architecture, this steering gear is a direct cross-platform component manufactured by BMW for both models.

Technical Specifications

• Type: Electric Power Steering (EPS) Rack and Pinion.

• Gear Teeth: Oblique (Helical) tooth design for smoother operation and reduced noise.

• Steering Ratio: Typically 2.1 turns lock-to-lock, providing the quick, responsive steering feel both cars are known for.

• Compatibility: * Toyota Supra (DB/A90/A91): 2019–Present.

  • BMW Z4 (G29): 2018–Present.

• Drive: Left-Hand Drive (LHD) specific.

Cross-Reference Part Numbers

In the automotive parts market, this unit is often listed under several interchangeable OEM and manufacturer numbers:

• BMW OEM: 32106898115, 32106896204, 32105A2F505, 32106892105.

• Toyota OEM: 44250-WAA01, 44250-WAA25, 44250-WAA27.

• Manufacturer Ref: BW138R(TU), 225A1ABF0-01.

Common Maintenance & Replacement Notes

1. Software Coding: Replacing this rack is not a simple “unbolt and bolt-on” procedure. Because the EPS motor has its own control module, the new rack must be initialized and coded to the vehicle’s VIN using BMW ISTA, Toyota Techstream, or an advanced OBD tool (like Esys).

2. Calibration: After installation, a Steering Angle Sensor (SAS) calibration and an electronic “end-stop” learning procedure are required to ensure the Lane Keep Assist and Electronic Stability Control (ESC) function correctly.

3. Tie Rods: Most replacement racks (especially remanufactured ones) are sold as the “center-take-off” unit only. You will likely need to transfer your existing inner and outer tie rods or purchase new ones (M14x1.5 thread).

4. Hardware: The steering rack is secured to the subframe with four high-strength stretch bolts. BMW/Toyota service manuals specify that these should be replaced with new hardware whenever the rack is removed.

Troubleshooting Symptoms

If you are replacing this due to a failure, common symptoms on the G29/A90 platform include:

• “Steering Effort Increased” warning message on the iDrive/Infotainment screen.

• Notchy or “binding” feel when turning the wheel at low speeds.

• Internal electronic short causing a total loss of power assistance (often caused by water ingress into the motor housing).