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Audi S6 Brake Light Switch Guide for the 2009-2018 Models

A faulty brake light switch in your S6 can trigger multiple warning lights and system failures, not just affect your brake lights.

4 minutes to read 2009-2018 Audi S6
Difficulty
2/5
Est. Time
0.75 hrs
DIY Doable?
✅ Yes
Shop Labor
$70-$100
⚠️ Drivable, but... — You can, but it is not recommended as your brake lights may not function, creating a serious safety hazard for you and other drivers.
Key Takeaways
  • A faulty brake light switch is a primary cause of the EPC light on an Audi S6.
  • Symptoms are not limited to brake lights; they also affect cruise control and the gear shifter.
  • This is a critical safety repair. Driving without functional brake lights is dangerous and illegal.
  • Replacement is straightforward and can be done by a DIYer with basic tools in under an hour.
The brake light switch, also known as a stoplight switch, is a simple but critical sensor. When you press the brake pedal, this switch sends a signal to several of your car's computers. Its primary job is to turn on the brake lights, letting drivers behind you know you are slowing down. On a modern vehicle like the Audi S6, it also tells the Engine Control Unit (ECU), Electronic Power Control (EPC), and stability control systems that the brakes are applied. This information is essential for features like cruise control, the automatic transmission's shift lock, and push-button start to work correctly.

Is Your Audi S6 Brake Light Switch Failing?

A failing brake light switch on the C6 and C7 generation Audi S6 can cause a surprising number of issues. Because the switch communicates with multiple vehicle systems, symptoms often go beyond the brake lights themselves. Understanding these signs can help you diagnose the problem quickly and avoid unnecessary repairs.

Common Symptoms of a Bad Brake Light Switch

  • EPC Light On: One of the most common signs of a bad brake light switch on an Audi is an illuminated Electronic Power Control (EPC) warning light on your dashboard. The system detects a conflict between the brake signal and other sensors, triggering a fault.
  • 🎬 See how the EPC light relates to your brake switch failure.
  • Brake Lights Don't Work or Stay On: The most obvious symptom is your brake lights failing to illuminate when you press the pedal, which is a major safety risk. Less often, the switch can fail in the 'on' position, causing the brake lights to stay on constantly and drain your battery.
  • Cruise Control Malfunction: If the switch is faulty, it cannot tell the cruise control system to disengage when you brake, so the system will often disable itself as a safety precaution.
  • Unable to Shift Out of Park: The shift interlock system requires a signal that the brake is pressed before allowing you to move the gear selector out of Park. A bad switch prevents this signal from being sent.
  • ABS/ESC Lights: The stability control system (ESC) and anti-lock brakes (ABS) may use the brake switch signal as part of their calculations. A faulty signal can cause these warning lights to appear.

No Recalls, But a Known Issue

While there are no specific recalls from the National Highway Traffic Safety Administration (NHTSA) for the brake light switch on the 2009-2018 Audi S6, this component's failure is a well-documented issue across many modern vehicles. The switch's constant use and its integration into multiple electronic systems make it a common wear-and-tear item.

Choosing the Right Aftermarket Brake Light Switch

When replacing the brake light switch, you don't necessarily need to buy an expensive Original Equipment (OEM) part from the dealer. High-quality aftermarket brands offer reliable alternatives that meet or exceed factory specifications.

  • Vemo: Vemo is a German brand that specializes in electronic components for European vehicles. Often sold with a "Q+" quality seal, Vemo parts are engineered to meet original equipment standards and are an excellent choice for an Audi S6. They are considered a top-tier aftermarket option.
  • Standard Ignition: Standard Motor Products (SMP) is a long-established and trusted aftermarket manufacturer. Their parts are widely used by professional repair shops and are known for their reliability and value. They provide a solid, dependable replacement option.

OEM vs. Aftermarket Quality

For a simple electronic switch like this, a high-quality aftermarket part from a reputable brand like Vemo or Standard Ignition is a smart choice. These parts provide the same function and reliability as the OEM version, often at a better price. The key is to avoid generic, no-name parts that may have poor quality control.

Brake Light Switch Replacement Cost

Replacing the brake light switch is an affordable repair. The part itself is not expensive, and the labor involved is minimal. Below are typical cost estimates for the Audi S6.

Part/Service Estimated Cost
New Aftermarket Part $41.75 - $65.03
New OEM Part $45 - $60
Shop Labor $70 - $100
Total Professional Replacement $110 - $165

Frequently Asked Questions (FAQ)

Can I replace the Audi S6 brake light switch myself?

Yes, this is a DIY-friendly job for most people. The switch is located above the brake pedal and is typically held in place by a clip or by twisting it into a bracket. The main challenge is the awkward position, as you'll need to work in the driver's footwell under the dashboard. The process usually involves removing a lower trim panel for access.

🎬 Watch this step-by-step guide to replacing the switch on your Audi.
How do I know the switch is bad and not the brake light bulbs?

If all your brake lights stop working at once, the switch is a more likely culprit than all the bulbs failing simultaneously. Furthermore, if you are also experiencing other electronic issues like the EPC light or cruise control problems, it strongly points to the switch being the root cause.

🎬 Watch this video to learn how to test your brake sensor.
Does the new brake light switch need to be programmed?

No, a new brake light switch does not require any programming. It is a simple plug-and-play component. Some switches are self-adjusting; after installation, pressing the brake pedal a few times will set the plunger to the correct depth.

What is the difference between a 2-pin and 4-pin brake light switch?

Different vehicle options (like cruise control) can require different switches. The number of pins corresponds to the number of separate circuits inside the switch. It is essential to order the correct part for your S6's specific configuration. Always verify the part by your vehicle's VIN or by visually inspecting the old switch before ordering.

Audi VW brake light switch replacing A4 A5 A6 Q5 etc 2009+ P057200 (Brake switch "A" circuit low)
Audi VW brake light switch replacing A4 A5 A6 Q5 etc 2009+ P057200 (Brake switch "A" circuit low)
EPC Warning light VW, Audi, Skoda, SEAT How to fix? Meaning & Problem solution🚘
EPC Warning light VW, Audi, Skoda, SEAT How to fix? Meaning & Problem solution🚘
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Brake Pedal and Brake Light Sensor Switch Testing and Replacement

Technical Specifications

OEM Part Numbers: 4F0945459B

The switch is typically a 2-pin or 4-pin plunger-style switch located on the brake pedal assembly. The number of pins depends on vehicle options. Always confirm the correct part number for your specific VIN before purchasing.

Wrenchy
Article researched & written by
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Meet Wrenchy → Updated Apr 19, 2026

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.

Year Coverage
This article covers the Brake Light Switch for:
  • Audi S6: 2009201020112012201320142015201620172018
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