P0715Input/Turbine Speed Sensor Circuit Malfunction
Get it checked soon
What it means
The input (turbine) speed sensor tells the transmission computer how fast the torque converter's output — the transmission's input — is spinning. Comparing it with engine speed and output-shaft speed is how the TCM knows what gear it's really in and when to shift. P0715 means that signal is missing or implausible, which forces the TCM to guess.
Is it safe to drive?
Get it checked soon
Expect symptoms, not just a light: harsh or mistimed shifts, RPM flare, a dead speedometer on some cars, and possibly limp mode locked into one gear. That's drivable to a shop, not drivable for weeks — erratic shifting is itself hard on a transmission. If it drops into limp mode on the highway, that's your cue to get it in now.
Common causes
Most likely first.
- A failed input/turbine speed sensor
- Wiring or connector damage on the way to the sensor
- Metal debris in the fluid clinging to the sensor tip — it's magnetic
- Transmission fluid problems — very low level or badly degraded
- Internal damage to the drum or reluctor the sensor reads — least common, most serious
What the live data shows
Where the car exposes transmission PIDs, input/turbine RPM disagreeing with engine RPM tells the story — the engine spinning at 2,500 while input speed reads zero or jumps around is a sensor or wiring signature. Around a shift, engine RPM flaring while road speed climbs smoothly suggests actual slip: a different, more serious finding.
A scanner that reads all 139 standard sensors shows you these readings live. ScanMyCar charts them as you drive, keeps the freeze-frame stored with the code, and pulls codes from every module — free, with any cheap Bluetooth adapter.
Typical fixes
Cheapest first, where honesty allows.
- Check the connector and wiring at the transmission first
- Check fluid level and condition; change it if it's dark or carries debris
- Replace the input/turbine speed sensor — external and affordable on many transmissions, internal on some
- If sensor and wiring test good, it's transmission-shop time
A guide, not a diagnosis. This page describes what P0715 generally means across OBD-II cars. What's actually wrong with your car depends on its live data and its history — and any repair decision deserves a proper diagnosis, whether that's you with a scanner or a professional with a lift.