P0720 Output Speed Sensor Circuit Malfunction

P0720 points to an output speed sensor circuit malfunction. The transmission or powertrain module is missing a believable output-shaft speed signal.

Code details

Generic OBD-II · P0

System: Transmission
Code type: Generic (SAE / ISO controlled)
Standard: SAE J2012 / ISO 15031-6

Diagnostic boundary

A diagnostic trouble code reports that a monitored test failed. It does not prove one specific part is bad, and manufacturer logic can add vehicle-specific conditions.

Do not diagnose shift quality problems until the output-speed signal is stable and plausible.

Symptoms of P0720

Harsh, delayed, or slipping shifts, or being stuck in one gear.
Check-engine light, sometimes with limp-home mode.
Flaring RPM or a shudder under load.

Common causes of P0720

Low or degraded transmission fluid.
A failing speed sensor, shift solenoid, or pressure-control circuit.
Wiring, connector, or internal hydraulic/mechanical faults.

Useful checks before replacing parts

Compare output speed with vehicle speed, input speed, commanded gear, and wheel-speed data while driving safely.
Inspect output speed sensor wiring, connector fit, sensor mounting, tone wheel condition, metal debris, and case connector terminals.
Check for speedometer faults, harsh shifting, limp mode, or companion ratio codes that depend on the output-speed signal.

Related OBD-II codes

These nearby transmission entries can help compare wording and pin down the fault area.