Symptoms
- Pedal pulses or vibrates during light, gentle braking
- Happens on dry, grippy roads where ABS shouldn't be needed
- ABS or traction control light may also be on
Likely causes
- CommonFaulty wheel speed sensor sending incorrect dataA bad sensor can make the ABS module think a wheel is slipping when it isn't.
- CommonDamaged or dirty tone ring (the toothed ring the sensor reads)Damage here confuses the sensor's speed readings.
- PossibleWiring issue at a wheel speed sensor connectorCorrosion or a loose connector can cause intermittent false readings.
- Less commonFailing ABS moduleLess common, but possible if all sensors test fine individually.
What to do
- Check if the ABS or traction control warning light is also on.
- Note whether the pulsing happens consistently or only occasionally.
- Have the code read at a shop, since a specific wheel sensor code will likely point to the cause.
- Have the flagged wheel speed sensor and its tone ring inspected for damage or debris.
- Have the sensor cleaned, repaired, or replaced based on what's found.
- Have the ABS module tested if all sensors check out fine individually.
Tools and parts
Wheel speed sensorSearch: “ABS wheel speed sensor for your car make and model”
When to call a pro
See a mechanic to scan and identify the specific sensor fault, since ABS shouldn't activate during normal, gentle braking on dry roads.
Safety
Generally low risk
Generally low risk for a careful person. Stop if anything looks different from what this guide describes.