The Lemon IndexThe transmission's output speed signal is erratic.
Fix soon. Book a shop visit this week. Stop driving if the car slips, shakes, overheats or warns you.
Failing output speed sensor. Then: wiring fault.
Owners named P0721 in 22 complaints to the U.S. government, most often on the Ford F-Series.
Models that report it most
Complaints that name P0721, by model. Raw counts, not a failure rate: popular models get more complaints. Tap a model for its years, mileage and what owners say fixed it.
P0721 by model: P0721 Ford F-Series (19)
Years owners report it on most: 2013 Ford F-Series · 2015 Ford F-Series · 2014 Ford F-Series · 2012 Ford F-Series
Transmission problems by year: Ford F-Series
The details
What P0721 means
The transmission's output speed signal is erratic.
Can I drive with P0721?
Fix soon. Book a shop visit this week. Stop driving if the car slips, shakes, overheats or warns you.
27% of the owner complaints that name P0721 also say the car loses power or goes into limp mode. A complaint can describe more than one problem, so this doesn't prove the code caused it.
Common causes of P0721
- Failing output speed sensor
- Wiring fault
A shop should confirm the cause with a scan and tests before replacing parts.
What owners describe
- Loses power or goes into limp mode: 27% of complaints
- Transmission slips or shifts hard: 18% of complaints
- Warning lights and electrical faults: 18% of complaints
Share of complaints naming the code whose text also mentions each problem.
Model years that report P0721 most
2013 Ford F-Series (8), 2015 Ford F-Series (5), 2014 Ford F-Series (4), 2012 Ford F-Series (2).
Related codes
P0720 P0722 P0725 P0729 P0717 P0716 P0715 P0713
Quick answers
What does P0721 mean?
Output Speed Sensor Circuit Range/Performance. The transmission's output speed signal is erratic.
Can I drive with P0721?
Fix soon. Book a shop visit this week. Stop driving if the car slips, shakes, overheats or warns you.
What causes P0721?
Failing output speed sensor; Wiring fault.
Counts: NHTSA owner complaints whose text names P0721. A complaint is an owner's report, not a diagnosis. Meanings: the standard SAE J2012 definitions in our own words; manufacturer codes only where verified for that make. General information, not repair advice for your car.