ABS and Traction Control Lights On - 2018 Q60 Red Sport

ClearTheCode admin answer:

When both the ABS (Anti-lock Braking System) and Traction Control System (TCS) lights illuminate simultaneously, it typically indicates a fault within a shared system component. These systems rely heavily on wheel speed sensor data, so issues there are a prime suspect.

Here are the most common causes for these warning lights:

1. Wheel Speed Sensor Failure: This is the most frequent culprit. Each wheel has a sensor that monitors its rotational speed. If one sensor fails or becomes dirty/damaged, the ABS and TCS modules lose crucial data, triggering both lights. A common diagnostic trouble code (DTC) associated with this is P0500 (Vehicle Speed Sensor Malfunction), though specific wheel speed sensor codes (e.g., C1101 for front left) are more precise.
2. ABS Module Malfunction: The ABS control module is the 'brain' of these systems. If it fails internally, it can cause both lights to come on. This is a more expensive repair but less common than a sensor issue.
3. Low Brake Fluid Level: While less common for both lights simultaneously without a brake warning light, extremely low brake fluid can sometimes trigger related warnings. Check your reservoir.
4. Wiring Issues: Damaged wiring or connectors leading to the wheel speed sensors or ABS module can interrupt signals, leading to false readings and warning lights.
5. Steering Angle Sensor: In some vehicles, a faulty steering angle sensor (which helps the TCS understand steering input) can also contribute to these lights, though it's less direct than a wheel speed sensor.

When to See a Shop:

• Immediately: While your car may seem to drive fine, the ABS and TCS systems are disabled when these lights are on. This means your vehicle will not have anti-lock braking or traction control in emergency situations, which significantly impacts safety. You should have this diagnosed and repaired as soon as possible.
• Diagnostic Scan: A professional shop will use an OBD-II scanner capable of reading ABS-specific codes (not just generic engine codes) to pinpoint the exact sensor or module causing the issue. This is crucial for an accurate and efficient repair.