Minimize driving — limp mode makes the car unpredictable. P0717 means the transmission's input/turbine speed sensor stopped sending a signal while the vehicle was moving. The controller can't tell how fast the input shaft is turning, which disrupts shift control and often triggers limp mode.
What P0717 means
The input (turbine) speed sensor reports how fast the transmission's input shaft or torque-converter turbine is spinning. The controller compares input speed to output speed to verify the gear ratio and to time shifts and lockup. “No signal” means the controller saw no reading while driving. It's most often a sensor, wiring, or connector fault, though a damaged tone ring or internal problem can also cause it. Note that the speedometer usually still works, because that comes from the output-speed sensor.
Symptoms
- Check engine light on
- Harsh or erratic shifting
- Transmission limp mode with limited gears
- Wrong-gear or slipping feel
- No torque-converter lockup
- Speedometer usually still works normally
Common causes
- Failed input/turbine speed sensor
- Wiring open or shorted, or a corroded connector
- Damaged sensor tone/reluctor ring
- Low fluid affecting internal operation
- Internal transmission damage
- Transmission controller fault (rare)
Severity & driving advice
Severity: Moderate-High — Losing the input speed signal commonly forces limp mode, and unpredictable shift behavior can be unsafe and hard on the transmission.
Can I drive? Minimize driving — limp mode makes the car unpredictable.
Diagnostic approach
- Scan live input vs output speed data — Compare the two speed signals while driving; a missing input speed with a valid output speed pinpoints the fault.
- Inspect the sensor connector and wiring — Check for corrosion, chafing, or an open circuit at the input/turbine sensor.
- Measure the sensor output/resistance — Verify the pickup produces a signal and matches specification.
- Check the reluctor ring — A chipped or contaminated tone ring can stop the sensor from reading.
- Verify transmission fluid — Low or dirty fluid can contribute; correct it and re-test.
- Consider internal inspection — If wiring and the sensor test good, an internal fault or controller issue may be responsible.
Make & model notes
General: Input/turbine speed sensors are typically magnetic or Hall pickups reading a rotating toothed element. A signal that drops to zero while the vehicle is clearly moving is the defining condition for P0717.
General: Don't confuse it with the output/vehicle-speed sensor (the P0720 group), which affects the speedometer — the input sensor mainly affects shift control.
FAQ
Can I drive with P0717?
Keep it to a minimum. The transmission may be in limp mode and shift unpredictably, which is unsafe and hard on the gearbox.
Why is my transmission in limp mode?
Without the input speed signal the controller can't verify gear ratios, so it defaults to a safe fixed gear to protect the transmission.
How is this different from the output speed sensor?
The input/turbine sensor reads the transmission's input shaft and affects shifting; the output speed sensor reads the output shaft and drives the speedometer.
What does P0717 cost to fix?
If it's the sensor or wiring, it's a moderate repair. If it's an internal tone ring or transmission damage, it can be significantly more.