What does P0720 mean?
The control module detected a condition described as “Output-speed sensor – circuit”. The code identifies the affected area, but it does not by itself prove which component has failed. The code describes the detected condition, not a guaranteed failed part. A reliable diagnosis also considers related codes, freeze-frame data, live values and the actual symptoms.
Possible causes
- Low or degraded transmission fluid
- Faulty speed or pressure sensor
- Shift-solenoid or hydraulic fault
- Mechanical wear or clutch/torque-converter problem
Common symptoms
- Harsh, delayed or missing gear changes
- Limp mode with one fixed gear
- Engine-speed flare or transmission slip
- Transmission warning
Sensible next checks
- Read additional transmission codes from the TCM
- Check fluid level and condition to manufacturer procedure
- Compare input and output speeds in live data
- Avoid driving if severe slip or pressure faults are present
Why does it return after clearing?
Clearing the code only removes the stored entry. If the underlying condition remains, the control module will set the code again after the next relevant monitor cycle. Save the data first, diagnose the cause, repair it and only then clear the code.