P0715: Input/Turbine Speed Sensor "A" Circuit
The transmission computer is not getting a reliable signal from the input speed sensor, which measures how fast the transmission input shaft spins.
What P0715 means
The input speed sensor, sometimes called the turbine speed sensor, reads how fast the transmission input shaft spins. The transmission computer compares that with output shaft speed to figure out which gear the transmission is in and whether it is slipping. RepairPal explains that P0715 is triggered when this sensor is not providing a reliable or rational signal, and without it the computer cannot shift properly from gear to gear. Most computers respond by holding a fixed gear in limp mode. The sensor itself is a common failure, along with wiring, connectors and metal debris that collects on its magnetic tip. Low fluid can also affect readings. Because these sensors may be on the outside of the case or deep inside the transmission, labor varies a lot by vehicle. Shops watch input speed on a scan tool while driving, measure the sensor output with a meter or scope and inspect the connector. A failed sensor is usually a moderate repair.
Common symptoms
- Check engine light on
- Harsh or erratic shifting
- Stuck in one gear or limp mode
- Speedometer problems on some vehicles
- Torque converter not locking up
Most common causes
- Failed input or turbine speed sensor
- Damaged or corroded wiring or connector
- Metal debris on the sensor tip
- Damaged reluctor on the input shaft
- Low fluid level
- Transmission control module fault
What to check yourself first
Check the transmission fluid level and condition. If your sensor is on the outside of the case, check its connector for oil or corrosion. Note whether the speedometer also acts up.
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 connector or wiring faults. |
| Transmission fluid change | $294-$356 | Low or burnt fluid causes many transmission codes. Check the correct fluid type for your transmission. |
| Replace transmission control module | $929-$1,006 | Only after the sensor and wiring are confirmed good. |
Typical US price ranges for parts and labor, not quotes. Your shop should confirm the cause with a diagnostic before replacing parts.
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Related codes
- P0720 Output Shaft Speed Sensor Circuit
- P0700 Transmission Control System (MIL Request)
- P0730 Incorrect Gear Ratio
- P0500 Vehicle Speed Sensor "A"
- P0741 Torque Converter Clutch Circuit Performance/Stuck Off