ABS Light Stays On in Your Toyota Alphard III? Here’s What to Check First

Why Is the ABS Light Always On?

If the ABS warning light on your Toyota Alphard III stays lit continuously, the system has detected a fault and disabled itself. In most cases, the culprit is a failed or dirty wheel speed sensor — a small magnetic component mounted behind each wheel hub that monitors how fast that wheel is turning. When one sensor stops sending a signal, the ABS computer can no longer compare wheel speeds, so it turns the warning light on and stores a trouble code.

What to Inspect First

Start with the easiest and most common fixes before replacing anything. The rear sensors on the Alphard III are especially exposed to road grime and corrosion. Here's my recommended order:

• Check the connector and wiring harness — Look for broken wires, chafed insulation, or corrosion at the sensor plug. A poor connection is often the real problem.
• Inspect the sensor tip and tone ring — Remove the sensor and wipe off any metal shavings or mud. Also check the toothed ring (reluctor ring) for damaged or missing teeth.
• Read the fault codes — Use an OBD-II scanner to see which wheel is implicated. A code like C0200 or C0205 points to the front-left or front-right sensor; C0210/C0215 point to the rear.
• Measure the sensor resistance — A healthy ABS sensor typically reads around 1–2 kΩ across its terminals. If you get an open circuit or a short, replace it.

Is It Safe to Keep Driving?

You can still drive with the ABS light on — the normal brake system remains fully operational — but you lose anti-lock protection, so wheels may lock up in a panic stop, especially on wet or loose surfaces. That's a serious safety trade-off. I recommend you have it diagnosed and repaired promptly. If the brake warning light also comes on, however, stop driving immediately and have the vehicle towed, because that indicates a hydraulic problem, not just an ABS sensor issue.

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