A Guide to the ABS Wheel Speed Sensor for the 2020-2025 Audi S8
Seeing ABS, ESC, or traction control lights on your Audi S8 dashboard? A wheel speed sensor could be the reason.
- A faulty ABS sensor will disable your S8's ABS and Electronic Stability Control (ESC) systems.
- Before replacing the part, inspect and clean the sensor and wheel hub area, as debris can cause the same warning lights per Audi TSB 2072304.
- Replacement is a DIY-friendly job for most, requiring basic tools and about an hour of time.
- For a high-performance car like the S8, choosing a quality aftermarket brand like Delphi or Beck Arnley is recommended over budget options.
Is Your Audi S8 Showing Brake-Related Warning Lights?
When you see a combination of warning lights for the ABS, ESC (Electronic Stability Control), and sometimes the tire pressure monitoring system (TPMS) on your 2020-2025 Audi S8, a faulty ABS wheel speed sensor is a very common cause. These sensors are exposed to harsh conditions like water, heat, and road debris, which can lead to failure over time. A failure will disable these important safety features, so it's a repair you should not ignore.
Pro Tip: Check for Debris Before You Replace
Audi has issued a Technical Service Bulletin (TSB 2072304) for vehicles up to 2024, including the S8 platform. It notes that dirt, grease, or metal shavings on the sensor's magnetic tip or the corresponding ring on the wheel bearing can cause an "implausible signal," triggering warning lights. Before you buy a new part, it's worth taking the wheel off and cleaning the sensor and the hub area. This simple step could save you the cost of a new sensor.
Symptoms of a Failing ABS Sensor
The signs of a bad wheel speed sensor are hard to miss. You will likely experience:
- ABS Warning Light: The yellow or orange ABS light on your dash will stay on.
- Traction/Stability Control Light: The light showing a car with squiggly lines (ESC/ASR) will also illuminate.
- Safety Systems Disabled: Your car will display a message that these safety features are turned off. Your normal brakes will still work, but you will not have anti-lock or stability assistance.
Choosing the Right Aftermarket ABS Sensor
For a high-performance vehicle like the Audi S8, the quality and accuracy of electronic sensors are very important. While an OEM (Original Equipment Manufacturer) sensor from an Audi dealer is always a safe choice, quality aftermarket parts can offer significant savings. Here’s a look at the available brands:
- Delphi: Delphi is a well-regarded brand and is often an original equipment supplier to many car manufacturers. For a European vehicle, choosing a brand with OEM experience is a smart move, making Delphi a strong aftermarket choice.
- Beck Arnley: This brand specializes in sourcing parts that match the original equipment. They often repackage OEM parts from the original factory supplier. This makes them a reliable option that should meet the fit and performance needs of your S8.
- Standard Ignition (SMP): Standard is a major aftermarket manufacturer with a wide range of products. Their sensors are typically a budget-friendly option. However, reviews can be mixed, with some users reporting success and others experiencing early failures. This brand may be best if cost is your primary concern.
On a complex car like the S8, using a low-quality sensor can sometimes cause persistent problems. For critical safety components, investing in a higher-tier aftermarket brand like Delphi or Beck Arnley is often worth the small extra cost.
Cost to Replace an Audi S8 ABS Wheel Speed Sensor
| Part Type | Estimated Cost |
|---|---|
| New Aftermarket Sensor | $48 - $84 |
| New OEM Sensor | $250 - $300 |
| Shop Labor | $146 - $215 |
| Total Professional Replacement (Aftermarket Part) | $194 - $299 |
Cost estimates are based on national averages and may vary by location and specific repair shop. The provided aftermarket price range is based on inventory pricing.
Frequently Asked Questions
Is it safe to drive with a bad ABS sensor?
You can drive the car, but it is not recommended for long. Your standard brakes will function, but the anti-lock (ABS) and stability control (ESC) safety systems will be turned off. This means your wheels can lock up during a hard stop, increasing stopping distance and reducing steering control.
Can I replace just one sensor?
Yes. You only need to replace the specific sensor that has failed. A diagnostic scan tool can read the trouble code to tell you which wheel is reporting the fault (e.g., 'left front wheel speed sensor'). The sensors do not need to be replaced in pairs.
Is replacing an ABS sensor a difficult DIY job?
For most people with basic tools, this is a very manageable job. It involves removing the wheel, taking out a single bolt (usually a 5mm hex), and unplugging the sensor. The most common problem is the sensor getting stuck in the hub due to rust. Using penetrating oil and gentle wiggling can help free it.
Do I need to reset the computer after replacing the sensor?
Once the new sensor is installed correctly, the warning lights on the dashboard should go off on their own after a short drive. You can use a basic OBD2 scanner to clear the codes immediately if you have one. No special programming is required.
Technical Specifications
OEM Part Numbers: 4M0927807C
The ABS wheel speed sensor for the Audi S8 is a magnetic hall-effect sensor. It is secured by a single bolt and connects to the main wiring harness inside the wheel well. Front and rear sensors may have different part numbers and cable lengths.
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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: