P0720: Output Shaft Speed Sensor Circuit
The transmission computer is not getting a reliable signal from the output speed sensor, which measures how fast the transmission output shaft spins.
What P0720 means
The output speed sensor sits near the back of the transmission and reads how fast the output shaft turns, which is directly tied to road speed. RepairPal explains that P0720 sets when the computer is not seeing a rational signal from the output sensor, or sees too much difference between input and output speeds, which can imply slipping. On many vehicles this sensor also drives the speedometer and feeds cruise control, so those can stop working too. Without a good output signal, the transmission computer cannot calculate gear ratio, so it may shift harshly or hold one gear. Common causes include a failed sensor, a damaged or corroded connector and metal debris stuck to the magnetic tip. KBB warns that driving long with this code can damage the transmission and lead to high repair bills. Shops compare output speed with wheel speed sensor readings on a scan tool, test the sensor signal and inspect wiring. A sensor replacement is often a quick external job.
Common symptoms
- Check engine light on
- Harsh or erratic shifting
- Speedometer not working or jumping
- Transmission stuck in one gear
- Cruise control not working
Most common causes
- Failed output speed sensor
- Damaged or corroded wiring or connector
- Metal debris on the sensor
- Damaged reluctor ring on the output shaft
- Low or dirty transmission fluid
What to check yourself first
Check whether the speedometer works; on many vehicles it uses the output speed sensor. Inspect the sensor connector on the transmission case for oil, corrosion or damage. Check fluid level and condition.
Typical fixes and what they cost
| Fix | Typical cost | Note |
|---|---|---|
| Replace transmission speed sensor | $395-$506 | Based on RepairPal speed sensor pricing. Input sensors mounted inside the transmission take more labor. |
| Electrical diagnosis to find a wiring or connector fault | $122-$179 | For wiring or connector problems. |
| Transmission fluid change | $294-$356 | Low or burnt fluid causes many transmission codes. Check the correct fluid type for your transmission. |
Typical US price ranges for parts and labor, not quotes. Your shop should confirm the cause with a diagnostic before replacing parts.
Related repair guides
- Subaru Forester CVT Shuddering or Slipping? Which Years Get a 10-Year Warranty and What a Replacement Costs
- Nissan Rogue CVT Shuddering or Slipping? Warranty, Repair Costs and Whether It's Worth Fixing
- Tacoma Transmission Hunting Gears or Shifting Hard? The Toyota Fixes by Year (2016-2025)
- GMC Sierra 1500 8-Speed Shudder or Harsh Shifts? The Fluid Flush Fix GM Recommends (and What It Costs)
- Ford Ranger Shifting Hard or Clunking? The 10-Speed Fix Ford Gives Dealers (2019-2023)
Related codes
- P0715 Input/Turbine Speed Sensor "A" Circuit
- P0500 Vehicle Speed Sensor "A"
- P0700 Transmission Control System (MIL Request)
- P0730 Incorrect Gear Ratio
- P0841 Transmission Fluid Pressure Sensor/Switch "A" Circuit Range/Performance