P0720 to P0723: transmission output speed sensor
The sensor that measures how fast the automatic gearbox's output shaft is turning has a circuit fault, no signal, an intermittent signal or an implausible reading.
SeverityModerateUsually not urgent today, but it can get worse if left.
Can you keep driving?Drive gently, check it soonWhat does P0720 mean?
The output speed is the gearbox's own measure of road speed. The gearbox computer uses it, with the input speed, to choose gears and check that each one engaged properly; on many cars it also feeds the speedometer. When it fails, shifts can come at the wrong moments or the gearbox may hold one gear, and the speedometer can drop to zero.
What causes P0720?
- A failed output speed sensor
- A damaged wire or corroded connector, often low on the gearbox where road spray reaches
- Metal debris on the sensor tip
- A loose sensor or a damaged reluctor on the output shaft
What to check first for P0720
- Check whether the speedometer still works
- Inspect the sensor and its connector, which often sit where water and dirt collect
- Compare the output speed on a scan tool with the road speed
- Read the ABS module too, since some cars share speed signals
Can you drive with P0720?
Usually drivable to a workshop, gently. Without a working speedometer, keep a close eye on your speed, and expect odd shifts or a fixed gear.
Since May 2018 an engine warning light that stays on is a major defect at the MOT, so the car fails until the fault is fixed.
Codes on this page
- P0720Output Speed Sensor Circuit
- P0721Output Speed Sensor Circuit Range/Performance
- P0722Output Speed Sensor Circuit No Signal
- P0723Output Speed Sensor Circuit Intermittent
Related codes
Checked on · Rafael Soares
These are the generic meanings every manufacturer shares. Each brand adds its own detail, so your car's handbook, its service information and a qualified mechanic have the last word. OdoKeep has no connection with any manufacturer, and the app does not read codes from the car.
