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ABS/ESP Warning Light On - 2017 Audi S5

0

Mike T. · rep 0 · May 25, 3:14 AM · 1 replies · solved · Question

Vehicle: 2017 Audi S5 Coupe

Hello everyone,

I'm reaching out because I've got a persistent ABS and ESP warning light illuminated on my dashboard in my 2017 Audi S5 Coupe. It came on a few days ago and hasn't gone off since. There's no noticeable difference in braking performance, but the lights are definitely concerning.

I've tried restarting the car multiple times, and even checked the brake fluid level (which is fine). I'm worried it might be something serious, especially since these systems are crucial for safety. I haven't had any recent work done on the car that would explain this.

Has anyone experienced this specific combination of warning lights on their S5 or another Audi? What was the cause, and what should I be looking at? Any insights would be greatly appreciated!

✓ Accepted solution

ClearTheCode Admin

ClearTheCode Team · rep 0 · May 25, 3:14 AM

0

ClearTheCode admin answer:

The illumination of both the ABS (Anti-lock Braking System) and ESP (Electronic Stability Program) warning lights simultaneously typically indicates an issue within a shared component or system, as these two systems are highly integrated. While braking might feel normal, their full functionality could be compromised.

Troubleshooting Steps:

  1. Check Brake Fluid Level: Ensure the brake fluid reservoir is filled to the correct level. Low fluid can trigger these warnings.
  2. Visual Inspection of Wheel Speed Sensors: Look at each wheel for any visible damage to the ABS sensor wiring or the sensor itself. Road debris can sometimes damage these.
  3. Scan for Diagnostic Trouble Codes (DTCs): This is the most crucial step. An OBD-II scanner capable of reading ABS/ESP specific codes will pinpoint the problem.

Common Causes:

  • Faulty Wheel Speed Sensor: This is the most common cause. A damaged, dirty, or failing wheel speed sensor (also known as an ABS sensor) will send incorrect or no data to the ABS/ESP control module, triggering the lights. Common OBD codes include C0034 - Wheel Speed Sensor - Open/Short or C0035 - Wheel Speed Sensor - Signal Implausible (often followed by a specific wheel designation).
  • Damaged ABS Sensor Wiring: The wiring harness leading to a wheel speed sensor can get chafed, cut, or corroded, leading to intermittent or complete signal loss.
  • Faulty ABS/ESP Control Module: Less common, but the control module itself can fail. This is a more expensive repair.
  • Steering Angle Sensor Issue: The ESP system relies on the steering angle sensor to know the steering wheel's position. A fault here can trigger ESP (and sometimes ABS) warnings.
  • Low Battery Voltage: While less likely to cause a persistent light without other symptoms, very low voltage can sometimes trigger various warning lights.

When to See a Shop:

Because ABS and ESP are critical safety systems, it's highly recommended to have your S5 professionally diagnosed as soon as possible. An Audi specialist will use a VCDS or ODIS diagnostic tool to read the specific fault codes, which are essential for accurately identifying the root cause. Driving with these lights on means your car's advanced braking and stability features may not function correctly in an emergency, increasing safety risks.

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