C0245: Wheel Speed Sensor Frequency Error

Can I keep driving?

What to do right now

1. 1Increase your following distance behind other vehicles in case the anti-lock braking system triggers unexpectedly.
2. 2Avoid harsh braking or abrupt steering inputs, especially in wet or icy road conditions.
3. 3Note whether your brake pedal pulses or vibrates at speeds below 20 km/h (12 mph) when slowing down.
4. 4Book an appointment with a local garage to read live wheel speed sensor data and isolate the fault.

Likely causes

Most likely first.

1. Likely

   Corroded or dirty ABS tone ring

   Road grit, rust, and metallic brake dust settle into the teeth of the reluctor ring over time. This obscures the magnetic profile and creates erratic frequency signals at low speeds.

2. Possible

   Cracked or swollen reluctor ring

   Rust forming beneath a pressed-on metal tone ring causes it to expand and fracture. The resulting wide gap breaks the rhythm of the sensor signal once per wheel revolution.

3. Possible

   Incorrect sensor air gap or improper seating

   Corrosion inside the sensor mounting bore can lift the sensor slightly away from the tone ring. A gap that is too wide weakens the magnetic pulse and scrambles the frequency reading.

4. Possible

   Failing wheel speed sensor or damaged wiring

   Internal sensor degradation or road debris catching the wiring harness creates electrical noise that the computer interprets as a frequency error.

5. Rare

   Worn wheel bearing with excessive play

   Severe internal bearing wear allows the wheel hub to wobble slightly under braking, altering the distance between the tone ring and the sensor pickup tip.

What you can check yourself

Park somewhere safe and level, engine off, before you start.

1. 1

   Check wheels and arches for debris

   Inspect the inner wheels and brake assemblies with a torch for heavy mud, snow, or road grime that could coat the sensor heads or tone rings.

2. 2

   Inspect visible sensor cables

   Park on level ground with the handbrake set, turn the steering to full lock, and check behind the front tyres for broken, stretched, or unplugged wiring harnesses.

3. 3

   Evaluate low-speed braking feel

   Drive at a crawling pace below 15 km/h (10 mph) in an empty car park and brake gently to determine if the pedal vibrates or chatters right as the car stops.

4. 4

   Verify tyre pressures and sizing

   Ensure all four tyres match the manufacturer sizes and recommended pressures in your handbook, as mismatched rolling diameters can confuse wheel speed calculations.

Typical prices in Ireland (€) and the UK (£), from an independent garage up to a main dealer. The total repair cost depends mostly on whether the reluctor ring is a standalone part or integrated into an expensive sealed wheel hub assembly or driveshaft.

When to go to a garage

• The brake pedal vibrates or resists normal pressure when you try to come to a halt in everyday driving.
• A red brake system warning light appears alongside the amber ABS light.
• You suspect a split reluctor ring or a failing wheel bearing that requires hydraulic press tools to replace.
• The ABS warning light remains on after basic external cleaning and visual inspections.

Questions drivers ask

Test rules here are for the National Car Test in Ireland (NCT) and the MOT in the UK. Elsewhere, check the regulations of your own country or state before going for a vehicle test.