What it means
TCM detects no signal from the input/turbine speed sensor while the engine is running and the transmission is in gear. Without this signal the TCM cannot compute slip, and the transmission usually enters limp mode.
At a glance
- Usually lights the check-engine light
- The engine or gearbox may go into limp mode
How it works
Input/turbine speed sensor A measures transmission input shaft speed and sends pulses to the TCM. P0717 sets when the TCM detects no signal while the engine is running and the transmission is in gear, preventing it from reliably calculating gear ratio or converter slip.
Common causes
Most likely first.
- Input speed sensor failed
- Wiring or connector fault
Symptoms
- Check engine or transmission warning light on
- Harsh, delayed, or missing shifts
- Possible limp mode (locked in one gear)
- Slipping or shuddering during gear changes
How to diagnose it
- Record freeze-frame data and confirm the code occurred with the engine running and the transmission in gear, then check whether input speed sensor A shows any live reading.
- Inspect sensor A's connector and harness for disconnection, corrosion, pin damage, or a broken wire.
- Use the manufacturer's wiring diagram to check the sensor circuit for an open, short, or poor connection.
- Test sensor A's power, ground, and output as applicable to its design, following the manufacturer's specified procedure.
- If the sensor and wiring pass, inspect the sensor target or internal transmission source for damage using vehicle-specific service information.
Common fixes
- Reconnect sensor A's connector and clean or secure terminals with poor contact.
- Repair an open, shorted, or damaged wire in the sensor A circuit.
- Replace input/turbine speed sensor A if it produces no output despite a sound circuit.
- Repair a damaged sensing target or internal transmission fault if the external circuit and sensor test correctly.
Can I keep driving?
Avoid driving if the transmission is locked in one gear, shifts unpredictably, or loses drive; arrange a tow if needed. Continued driving without input speed information can cause harsh operation and increase transmission wear.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.