Audi S8 (2006-2010) ABS Wheel Speed Sensor: A Complete Replacement Guide
Diagnose and fix your S8's ABS, ESP, and traction control warning lights by choosing the right sensor.
- This guide is for the D3 generation Audi S8 (2006-2010); parts differ for other years.
- Warning lights for ABS, ESP, and Parking Brake are the primary symptoms of a failed sensor.
- Before replacing the sensor, inspect the wiring harness and the magnetic ring on the wheel bearing for damage.
- For best results, choose a premium aftermarket brand like Bosch or Hella to ensure compatibility and longevity.
A Note on Vehicle Years: 2003-2012 Audi S8
This guide focuses specifically on the D3 generation Audi S8, sold from 2006 to 2010. The user-provided year range of 2003-2012 covers three different S8 generations (D2, D3, and D4). Parts are not interchangeable between these generations. If you own a 2003 (D2) or 2012 (D4) model, you must verify your specific part numbers before ordering.
Symptoms of a Failing ABS Sensor
When an ABS sensor fails on your S8, the car will usually alert you with several dashboard warning lights. The most common sign is the ABS light itself turning on and staying lit. You will likely also see warnings for the ESP or traction control system, and sometimes a parking brake malfunction alert.
You may also notice changes in how the car drives:
- Disabled Safety Features: The most significant issue is that your anti-lock brakes and stability control will not work. In an emergency stop, your wheels could lock up and skid.
- Brake Pedal Feel: The brake pedal might feel unresponsive, spongy, or pulsate even during normal braking.
- Speedometer Issues: In some cases, a bad sensor can cause the speedometer to behave erratically or stop working.
Check These First!
Sometimes, other issues can mimic a failed sensor. Before buying a new part, check for a damaged magnetic ring on the wheel bearing, which can get corroded or dirty and cause an 'implausible signal' error. Also, inspect the sensor's wiring harness for cracks, corrosion, or damage, as this is a common failure point. A weak battery can also cause random electronic faults on these vehicles.
Choosing the Right Aftermarket ABS Sensor
When it comes to electronic parts on a high-performance vehicle like the S8, quality matters. While budget parts are available, they have a higher risk of failing early or not working correctly out of the box. For a critical safety component like an ABS sensor, it is often best to choose a brand known for quality.
Aftermarket Brand Tiers for Audi S8
| Tier | Brands | Assessment |
|---|---|---|
| Premium (OEM Quality) | Bosch, Hella, Delphi | These brands are often the original equipment manufacturers for Audi. They offer the best fit and highest reliability, ensuring the sensor communicates correctly with your S8's complex systems. Bosch and Hella are highly recommended by mechanics for European cars. |
| Mid-Grade | Standard Ignition (SMP), Bremi | These brands are generally considered reliable and offer a good balance of price and quality. While not always the OEM supplier, they are a solid choice for a dependable repair. |
| Economy | URO Parts, Vemo, Facet | These brands provide a low-cost alternative. Vemo is specifically focused on European vehicles and can be a decent budget option. However, brands like URO Parts have mixed reviews for electronic components and may have a higher failure rate. Use with caution for critical systems. |
Frequently Asked Questions (FAQ)
Can I replace just one ABS sensor?
Yes. You only need to replace the sensor that has failed. A diagnostic scan tool is needed to read the specific fault code (like C0035) which will tell you which wheel sensor is bad (e.g., front left, rear right). The sensors are often the same for all four corners on the D3 S8, but always verify the part number.
Is this a difficult job to do myself?
No, for a DIYer with basic tools, this is a straightforward job. It involves removing the wheel, unplugging the connector, and removing a single hex bolt that holds the sensor in the wheel hub. The most common difficulty is the old sensor being seized by corrosion, which may require penetrating fluid and patience to remove. The estimated time is 30-60 minutes per wheel.
Do I need to reset the computer after installing a new sensor?
Typically, no special programming is needed. After you replace the faulty sensor, the warning lights on the dashboard should go off on their own after a short drive. You should clear the old fault codes from the ABS module with a scanner as a final step.
What tools are required for the replacement?
You will need a jack and jack stands, a lug wrench to remove the wheel, a 5mm hex bit socket for the sensor bolt, and possibly a small wire brush to clean the mounting hole. Penetrating fluid like WD-40 is highly recommended to help remove the old sensor. Applying a small amount of brake grease to the new sensor body (avoiding the tip) can make future replacement easier.
Pro Tip: False Sensor Codes
Be aware that a failing ABS control module can sometimes throw a fault code for a perfectly good wheel speed sensor. If you replace a sensor and the same error code returns immediately, the problem may lie with the ABS module itself or the wiring between the sensor and the module.
Technical Specifications
OEM Part Numbers: 4E0927803F 4E0927803D 4E0927803A 4E0927804F 4E0927804D
The sensor for the D3 S8 is typically a 2-pin Hall effect sensor that includes the wiring harness. It is held in place by a single bolt. On many D3 platform cars, the same sensor part number is used for all four wheels.
We Have This Part in Stock
The information in this article is provided for general reference and educational purposes only. Vehicle specifications, procedures, and part compatibility can vary by production date, trim level, and region. Always consult your vehicle's factory service manual and verify part numbers before purchasing or performing repairs. Safety-critical components such as airbags, seat belts, and braking systems should be installed by a qualified professional.
- Audi S8: