What is an ABS or wheel speed sensor?

The ABS (Anti-lock Braking System) relies on wheel speed sensors to monitor how fast each wheel is rotating. These sensors feed data to the ABS control module, helping prevent wheel lock-up under hard braking. If a sensor fails, the ABS warning light will usually appear on your dashboard and the system may stop working correctly.

Why do you need an ABS sensor?

ABS sensors are a vital safety feature, ensuring your car can maintain steering control during sudden braking or on slippery roads. A faulty sensor means your ABS may not activate when needed, increasing your stopping distance and the risk of skidding. Keeping sensors in good condition is also required to pass a WOF inspection in New Zealand.

Common signs your ABS sensor needs replacing

• ABS warning light illuminated on the dashboard
• Loss of ABS function during emergency braking
• Pulsating brake pedal even under normal braking
• Inconsistent speedometer readings (in some vehicles)
• Other brake system warning lights appearing together

If you notice these issues, a diagnostic check will confirm whether a wheel speed sensor needs replacing.

What happens during an ABS sensor replacement?

A mechanic will first confirm which sensor has failed using a scan tool. The faulty sensor is then removed from the wheel hub or suspension assembly and replaced with a new unit. The ABS wiring is checked for damage or corrosion before resetting the fault codes. A road test is performed to ensure the ABS light is cleared and the system functions correctly.

How much does an ABS sensor replacement cost?

Replacing a single ABS wheel speed sensor typically costs between $250 and $450 in New Zealand, depending on the make and model of your vehicle. Premium or European cars may cost more due to complex sensor designs. If multiple sensors or additional wiring repairs are needed, costs can increase further. You’ll always receive an upfront quote before work begins.

Is it safe to drive with a faulty ABS sensor?

No. While your normal braking system will still function, the anti-lock feature will not engage if a sensor is faulty. This increases the risk of skidding and losing control in an emergency stop. Driving with a faulty sensor may also cause your car to fail its WOF. For safety and compliance, it’s best to replace the sensor promptly once a fault is detected.