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P0720: Output Speed Sensor Circuit

Severity: Medium Avoid towing, steep loads, and prolonged driving until diagnosed. Stop and arrange recovery if the transmission slips, loses drive, overheats, or bangs into gear; driving through slip can cause further damage.

What does P0720 mean?

The transmission output-speed circuit has a malfunction. Output rotation helps determine road speed and shift timing; depending on the model the same data may also feed the speedometer.

Generic OBD-II definition: Output Speed Sensor Circuit. Confirm applicability in your vehicle service information.

Common causes

  • Failed output-speed sensor
  • Damaged output-sensor wiring
  • Poor connection or shared circuit fault

Symptoms

  • Delayed shifts
  • Speedometer fault on some vehicles
  • Check engine light

Diagnostic focus

The output sensor is not necessarily the same part as a wheel-speed sensor. Trace the vehicle-specific speed-data path before replacing anything at the hubs.

Can I keep driving with P0720?

Severity: Medium Avoid towing, steep loads, and prolonged driving until diagnosed. Stop and arrange recovery if the transmission slips, loses drive, overheats, or bangs into gear; driving through slip can cause further damage.

If the check engine light is flashing or the car runs badly, stop driving and have it checked.

Typical fixes

  • Identify the output-speed signal source
  • Inspect the case connector and harness
  • Test supply and signal against the transmission diagram

Related codes

P0721
Output Speed Sensor Range/PerformanceP0722
Output Speed Sensor Circuit No SignalP0500
Vehicle Speed Sensor "A"

Sources & review

Definitions and diagnostic background checked 2026-11-06. Generic guidance, not a substitute for the service procedure for your exact year, engine, and transmission.