OBD CodesWhat it means
An automatic gearbox has a sensor on its input shaft and one on its output shaft. By comparing them the computer knows which gear is engaged and whether anything is slipping. If either signal is lost, it cannot time the gear changes.
Codes in this group
| Code | Meaning |
|---|---|
| P0715 | Input (turbine) speed sensor circuit fault |
| P0716 | Input speed sensor reading out of range |
| P0717 | Input speed sensor shows no signal |
| P0718 | Input speed sensor signal cuts in and out |
| P0720 | Output speed sensor circuit fault |
| P0721 | Output speed sensor reading out of range |
| P0722 | Output speed sensor shows no signal |
| P0723 | Output speed sensor signal cuts in and out |
Bank 1 is the side of the engine that has cylinder 1. Sensor 1 is before the catalytic converter and sensor 2 is after it. More terms explained.
What you may notice
- Harsh or erratic gear changes
- Gearbox stuck in one gear
- Speedometer not working (output sensor on some cars)
Common causes
Most likely first:
- A failed speed sensor
- Metal particles stuck to the sensor tip
- Damaged wiring or a corroded connector
- Low or dirty fluid
What to check first
- These sensors are often simple to replace from outside the gearbox, but on some they are inside
- Have the fluid level and condition checked at the same time
Have a mechanic confirm. A fault code tells you which system reported a problem, not which part has failed. The same code can have several causes, and they differ between car models. Use this page to understand the code, then have a qualified mechanic test the car before any part is replaced.
After the repair
Once the cause is fixed, the code can be cleared with a scan tool, or the warning light goes out by itself after several trips without the fault. Clearing a code without fixing the cause only hides it for a while. More about clearing codes.
Related codes
Transmission control system request (P0700), Transmission range (gear selector) sensor (P0705), Transmission fluid temperature (P0218), Incorrect gear ratio (P0729), Torque converter clutch (P0740), Shift and pressure control solenoids (P0745), Clutch pedal position sensor (manual gearbox) (P0805). All codes.
Written in November 2026. These are generic OBD-II codes, the same on all makes. Causes and repair steps differ between models.