Guide to the 2008-2018 Audi S5 ABS Wheel Speed Sensor
Learn why your ABS and traction control lights are on and how to choose the right replacement sensor for your S5.
- A bad ABS sensor on an S5 will typically trigger ABS, ESC, and Parking Brake warning lights all at once.
- For reliable performance, choose a premium aftermarket brand like Bosch or Hella, as they are often the original equipment suppliers for Audi.
- Replacement is a simple DIY job for most, requiring basic tools to remove one bolt and a connector, but be prepared for the old sensor to be stuck.
- Check for wiring damage near the firewall, as a TSB was issued for 2009-2014 models for this known issue.
Understanding ABS Wheel Speed Sensor Failure in Your S5
A faulty ABS wheel speed sensor is a common issue that will immediately trigger several warning lights on your dashboard. Because the sensor provides data to multiple safety systems, you'll typically see alerts for the ABS, Electronic Stability Control (ESC), and sometimes the parking brake system all at once. Ignoring a bad sensor means these important safety features will not work, which can be dangerous in an emergency braking situation or on wet and slippery surfaces.
Common Symptoms of a Bad Sensor
When a wheel speed sensor fails, your S5 will let you know right away. The most common signs include:
- ABS Warning Light: The most direct indicator of a problem with the anti-lock braking system.
- Traction Control (ESC/ASR) Light: Since traction control relies on wheel speed data, this light will also illuminate.
- Parking Brake Malfunction Light: Many Audi models will display a parking brake fault when an ABS sensor fails.
- ABS System Disabled: During a hard stop, you may notice the wheels lock up because the ABS is no longer functioning.
In some cases, a bad sensor can also affect other systems, but the dashboard warning lights are the most reliable symptom. Sometimes, the issue isn't the sensor itself but damage to the wiring harness that connects to it, which can cause the same errors.
🎬 Watch how to diagnose common Audi ABS and traction light causes.Known Issues: TSB for Wiring Harness Damage
Audi issued Technical Service Bulletin (TSB) 45 13 07 2033412/2 for 2009-2014 S5 models. It notes that the insulation for the ABS wheel speed sensor wiring can be damaged where it passes through the left side bulkhead. This can lead to corrosion and an electrical fault or incorrect signal from the sensor, triggering multiple warning lights. Before replacing a sensor, it's wise to inspect the wiring harness for any visible damage or corrosion, as a simple wire repair might solve the problem.
🎬 See a step-by-step ABS sensor replacement on an Audi B8 chassis.Choosing the Right Aftermarket ABS Sensor
When it comes to electronic parts on a German car like your S5, quality matters. While OEM parts are always an option, several aftermarket brands offer excellent quality, often for a much lower price. It's generally recommended to stick with brands known to be OEM suppliers or those with a strong reputation for reliability.
Brand Quality Tiers for Your Audi S5
Tier 1: OEM Supplier & Premium Aftermarket
- Bosch: Bosch is a very common original equipment manufacturer for Audi and other German brands. Choosing a Bosch sensor is the closest you can get to the factory part's quality and reliability. They are known for precise signals and long life.
- Hella: Another top-tier German brand known for making quality electronic components. Hella is a trusted choice for European vehicles.
Tier 2: Reputable Aftermarket Brands
- Delphi: A well-known brand that produces reliable electronic parts, including ABS sensors. Many users have good experiences with Delphi components.
- Beck Arnley: This brand often sources parts from the original factory suppliers and repackages them. This means you might get an OEM-quality part without the OEM price tag.
- Standard Ignition (SMP): A long-standing company that produces dependable replacement parts that are designed to match original specifications.
Tier 3: Economy Options
- Vemo: Vemo specializes in parts for European cars and can be a good value option. However, some users report mixed experiences regarding long-term quality.
- URO Parts: URO Parts offers budget-friendly components. While they meet basic specifications, they are generally considered a lower-tier option and may not have the same lifespan as premium brands.
- Facet: This brand provides a wide range of sensors and can be a cost-effective choice for a repair.
Pro Tip: For critical electronic sensors on an Audi, spending a little more for a Tier 1 or Tier 2 brand like Bosch or Hella can prevent you from having to do the job twice. Cheaper sensors have a higher chance of failing early or providing an incorrect signal.
Estimated Costs for Replacement
| Part Type | Estimated Cost |
|---|---|
| New OEM | $150 - $250 |
| New Aftermarket | $28.86 - $94.32 |
| Shop Labor | $100 - $200 |
Frequently Asked Questions (FAQ)
Can I replace just one ABS sensor?
Yes. You only need to replace the specific sensor that has failed. A proper diagnostic scan tool will tell you which wheel is reporting a fault (e.g., "Left Front ABS Wheel Speed Sensor").
Are the front and rear sensors the same?
No, front and rear sensors typically have different part numbers and are not interchangeable. On some S5 models, the left and right sensors on the same axle may be the same, but you must verify the correct part for each specific location before ordering.
Is replacing an ABS sensor a difficult DIY job?
For most home mechanics, this is a straightforward job. The sensor is usually held in by a single bolt and has an electrical connector. The most common difficulty is the sensor seizing in the wheel hub due to rust, which may require penetrating oil and patience to remove.
🎬 Learn how to change an ABS wheel speed sensor on Audi/VW.Do I need to reset the computer after replacing the sensor?
Yes. After installing the new sensor, you will need to use an OBD2 scanner to clear the fault codes from the ABS control module. Once the codes are cleared, the warning lights on your dashboard should turn off.
What happens if I ignore a bad ABS sensor?
Your car will still drive and brake normally under most conditions. However, the ABS, traction control, and stability control systems will be disabled. This is a significant safety risk, especially in emergency situations or on slippery roads, as the wheels can lock up or spin without computer assistance.
Helpful Videos
Technical Specifications
OEM Part Numbers: WHT003856 WHT003857 WHT003858 WHT003859 4M0927803C
The ABS wheel speed sensor for the Audi S5 is a two-pin magnetic sensor that mounts to the wheel hub assembly. Front and rear sensors are different, and in some cases, left and right are also specific. Always verify the part number for the correct wheel location before purchase.
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 S5:
- 🎬 Helpful Videos
- 🛍️ Shop This Part
- Understanding ABS Wheel Speed Sensor Failure in Your S5
- Common Symptoms of a Bad Sensor
- Known Issues: TSB for Wiring Harness Damage
- Choosing the Right Aftermarket ABS Sensor
- Brand Quality Tiers for Your Audi S5
- Estimated Costs for Replacement
- Frequently Asked Questions (FAQ)
- 🎟️ Get 5% Off