P0720 serious

Output Speed Sensor Circuit Malfunction

What does P0720 mean?

The P0720 code means the vehicle's onboard diagnostic system has detected: Output Speed Sensor Circuit Malfunction. This is a serious severity code.

Common Symptoms

  • Incorrect speedometer reading or no reading
  • Erratic transmission shifting
  • ABS and traction control lights may illuminate
  • Check Engine Light on

Probable Causes (Ranked by Likelihood)

  • Failed output shaft speed sensor Very High
  • Metal debris on sensor tip Moderate
  • Damaged wiring to output speed sensor Moderate

Step-by-Step Diagnostic Procedure

  1. Monitor output speed sensor on live data. Should track vehicle speed proportionally.

  2. Inspect sensor for metal debris accumulation on the sensing tip.

  3. Test sensor resistance and compare to spec.

  4. Check wiring between sensor and TCM.

Frequently Asked Questions

Will P0720 cause the speedometer to stop working?

On some vehicles, the speedometer is driven by the output speed sensor signal. A failed sensor will cause an inaccurate or dead speedometer. On others, the ABS wheel speed sensors drive the speedometer independently.

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