C0031 Left front wheel speed sensor circuit fault (Ford and Lincoln)

C0031 left front wheel speed sensor circuit

Severity not verified — if the car runs badly, have it inspected

The sources describe the fault and the warning lamps but not how safe it is to drive; ABS and stability control are safety-critical, so have it checked.

It gets more serious if:

  • Stop: The red brake warning lamp comes on, the pedal feels soft or low, or steering assist is lost along with the ABS lamp.

Safety-critical system: explanation only, no DIY steps. Source: how we rate severity

C0031 in short

On Ford and Lincoln vehicles C0031 is a left front wheel speed sensor circuit fault stored by the ABS module. Ford bulletins tie it to sensor harness rubbing, metal contamination on the sensor or ring, and a misrouted brake hose. Normal braking usually continues, but ABS and stability control may be off.

The ABS module reads a speed signal from each wheel. C0031 on Ford and Lincoln means the left front sensor signal is missing, erratic or out of range, so anti-lock, traction and stability control cannot use that wheel.

Ford bulletins that list C0031 with C0034 (right front) describe three different physical causes: a sensor harness rubbing on the front wheels (2020 Escape and Corsair), metal debris on sensors or rings (2020-2021 Explorer and Aviator), and an incorrectly routed front brake hose (2021 F-150). One owner reported the ABS, traction control and airbag lamps all lit with C0031 and a communication code, and the sensor replacement did not clear them.

Other makers use C0031 with their own wording (Chrysler and Jeep lists describe a left front sensor too), but this page only covers Ford and Lincoln. Brakes are safety-critical, so there are no do-it-yourself steps.

Pick your make

C0031 is a manufacturer-specific code: its meaning depends on who built the car.

Other makes: meaning not verified. Check with a scan tool that reads manufacturer definitions.

Most likely causes

  1. Wheel speed sensor harness rubbing or damaged

    Supported by vehicle data
    Why it ranks here
    Ford TSB 20-2323 names a sensor harness rubbing on the front wheels for C0031 on 2020 Escape and Corsair, and a Lincoln owner's dealer confirmed a left front circuit fault.
    What would change this
    Rises if the signal drops out when the wheel is turned or the harness is moved. Falls if the harness is clean and tests normal.
    How to test the brake system control module (abs module)

  2. Metal debris on the sensor or sensor ring, or a bearing-area fault

    Supported by vehicle data
    Why it ranks here
    Ford SSM 49433 (Explorer, Aviator) names metal contamination, and SSM 47785 (Transit) pairs C0031 with front wheel bearing noise and has the sensor cleaned.
    What would change this
    Rises if debris is found on the sensor or ring, or noise comes from the front wheel. Falls if both are clean.

  3. Front brake flexible hose routed against the sensor wiring

    Possible — needs testing
    Why it ranks here
    Ford TSB 21-2295 names an incorrectly routed hose for rubbing noise with C0031 and C0034, but only on 2021 F-150.
    What would change this
    Rises on an F-150 with a rubbing noise at the front. Falls on other models.

What to test first

Start at step 1. Each result tells you what it means and where to go next.

  1. Ask a shop to read the ABS codes with their suffixes, check the left front wheel speed sensor signal and harness, and look for a Ford bulletin for your VIN.

    Best left to a shop

    Warning:Brake faults are safety-critical; leave diagnosis and repair to a qualified shop.

Symptoms

  • ABS lamp on
  • Traction or stability control lamp or message
  • Red brake lamp on, soft pedal, or lost steering assist Gets more serious: stop and have it checked.

How to fix

This is a safety-critical system, so we explain the code but don't give repair steps. Have it inspected by a qualified technician.

Parts and cost context

  • Brake system control module (ABS module):Wheel speed sensors and harness repair kits are the parts the Ford bulletins name; labor varies, get a quote.

Labor varies by vehicle and shop; get a quote before you approve a repair.

Compare used part prices on PartPriceGuide

On your vehicle

Ford

  • 2020 · Escape

    Supported by vehicle data

    Ford TSB 20-2323 ties C0031 to the sensor harness rubbing on the front wheels on early-build 2020 vehicles. Bulletin currency not verified.

  • 2020–2021 · Explorer

    Supported by vehicle data

    Ford SSM 49433 lists C0031 with the other wheel speed codes and points to metal contamination. Bulletin currency not verified.

  • 2015–2019 · Transit

    Supported by vehicle data

    Ford SSM 47785 pairs C0031 and C0034 with front wheel bearing noise. Bulletin currency not verified.

  • 2021 · F-150

    Supported by vehicle data

    Ford TSB 21-2295 covers a rubbing noise with C0031 and C0034 on early-build 2021 trucks. Bulletin currency not verified.

  • TSB 20-2323 (ford)Status unverified

    ABS and stability lamp with C0031, C0034 and/or C0051

    2020escape · NHTSA 10180536

    Inspect the wheel speed sensor harness and install the pigtail service kit.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

  • SSM 49433 (ford)Status unverified

    ABS lamp with C0031, C0034, C0037 and/or C003A

    2020–2021explorer · NHTSA 10186400

    Check sensors and rings for metal contamination before replacing them.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

  • SSM 47785Status unverified

    Front wheel bearing noise or C0031 and/or C0034

    2015–2019transit · NHTSA 10155560

    Remove and clean the front wheel speed sensor and see whether noise and codes clear.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

  • TSB 21-2295Status unverified

    Rubbing noise and/or C0031 and/or C0034

    2021f-150 · NHTSA 10202699

    Inspect the front brake flexible hose routing.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

Lincoln

  • TSB 20-2323 (lincoln)Status unverified

    ABS and stability lamp with C0031, C0034 and/or C0051

    2020corsair · NHTSA 10180536

    Inspect the wheel speed sensor harness and install the pigtail service kit.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

  • SSM 49433 (lincoln)Status unverified

    ABS lamp with C0031, C0034, C0037 and/or C003A

    2020–2021aviator · NHTSA 10186400

    Check sensors and rings for metal contamination before replacing them.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

  • C0037Left rear wheel speed sensor circuit fault

    Same system Supported by vehicle data

    Ford SSM 49433 lists C0031 with C0034, C0037 and C003A, the other wheel speed sensor circuits.

All ABS, traction and stability control codes

C0031 questions

What does C0031 mean on a Ford?

A left front wheel speed sensor circuit fault in the ABS module. The suffix after the dash shows the failure type.

Is it safe to drive with C0031?

Normal braking usually still works, but anti-lock and stability control may be off. Stop if the red brake lamp comes on or the pedal feels wrong.

Sources and review

  1. NHTSA complaints ODI 11745133 (Lincoln MKZ) and 11073267 (Ford Fusion) — NHTSA ODI
  2. Ford TSB 20-2323: ABS and stability lamp with C0031, C0034 and/or C0051 on Escape and Corsair — Ford via NHTSA
  3. Ford SSM 49433: ABS lamp with C0031, C0034, C0037 and/or C003A on Explorer and Aviator — Ford via NHTSA
  4. Ford SSM 47785: front wheel bearing noise or C0031 and/or C0034 on Transit — Ford via NHTSA
  5. Ford TSB 21-2295: rubbing noise and/or C0031 and/or C0034 on F-150 — Ford via NHTSA
Last reviewed
Written by
Saurabh K.
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