ABS Light On in Your Mercedes GLA H247? What to Check and Is It Safe to Drive?

If the ABS light on your Mercedes-Benz GLA (H247) stays on continuously, it's a prompt from the stability control system that something isn't right with wheel-speed data — though not always the wheel sensor itself. In most cases we see, a failed or weakened speed sensor is the culprit, but other causes include a damaged reluctor (tone) ring, broken wiring, low brake fluid, or a faulty ABS module. A proper diagnostic scan will show which wheel is affected and help separate the likely causes.

What to check first

After reading the fault codes and viewing live sensor data, inspect the relevant wheel in this order:

• Connector and wiring: Look for corrosion, water in the socket, a loose lock tab, or chafing against the fender liner. Gently wiggle the harness while watching the scan tool to duplicate the fault.
• Sensor tip and reluctor ring: Remove the sensor if accessible and check its tip for rust or debris, then carefully inspect the toothed ring behind the brake disc for cracked or missing teeth.
• Brake fluid level: A low fluid level can occasionally trigger the ABS light, though usually the brake warning light would also be on. Top up only if the level is below minimum and the brake pads are not worn out.

On the GLA H247, the wheel speed sensor is often a separate part that can be replaced individually, without having to swap the entire wheel bearing or hub. On some trims and model years, however, the sensor may be mounted into the hub assembly — so do confirm the exact sensor and procedure for your specific vehicle before ordering parts. Replacing the whole hub should be treated as a fallback if the bearing itself is worn or the sensor cannot be serviced separately.

Is it safe to drive?

In normal conditions, yes — your braking system will still stop the car because the hydraulic foundations are not affected. The car will lack ABS intervention, traction and stability control, so on wet, icy, gravel, or panic-braking situations you have to rely on your own braking and be more cautious. If you also see a red brake warning light, or if the pedal feels low or soft, do not drive and have the brake system checked first. Otherwise, ask for a scan and get the system repaired as soon as practical.

This material is AI-generated and for informational purposes only — it does not replace an in-person diagnosis by a qualified mechanic.