P0717
Input/Turbine Speed Sensor A Circuit No Signal
When a vehicle powertrain module registers the fault code P0717, it points directly to an internal system malfunction identified as "Input/Turbine Speed Sensor A Circuit No Signal". Operating your engine under this condition may degrade long-term fuel maps.
Driver's Summary
Your vehicle's computer logged P0717 after detecting a malfunction in the input/turbine speed sensor a circuit no signal system. Typical symptoms include transmission will not shift, stuck in 1st gear or limp mode. Stop driving as soon as it is safe to do so. This fault can lead to expensive secondary damage if left unaddressed.
Symptoms
Transmission will not shift, stuck in 1st gear or limp mode
Common Causes
- Dead input speed sensor
- Unplugged sensor connector
- Cut or broken wiring harness
- Failed TCM
How to Fix
- 1 Replace input/turbine speed sensor
- 2 Reconnect sensor plug properly
- 3 Repair broken wiring
- 4 Test and replace TCM
Technical Explanation
Code P0717 is confirmed when the ECM's diagnostic algorithm detects a parameter deviation that persists across a defined number of consecutive drive cycles. The TCM also cross-references engine torque demand, throttle position, and vehicle speed to determine whether the actual gear ratio deviation is genuinely abnormal or a result of expected torque converter slip during aggressive acceleration. The fault remains stored in memory even after the MIL is cleared; it becomes a confirmed DTC after failing two consecutive drive cycles, and the PCM logs a freeze frame record of the engine's exact operating state at the moment of detection.
Is It Safe to Drive?
Driving with an active P0717 fault risks accelerating damage to dead input speed sensor and related components. The longer the fault persists, the more expensive the eventual repair becomes — what starts as a sensor or solenoid issue can escalate to major mechanical failure.
Mechanic's Pro Tip
The most common mistake with P0717 is replacing the sensor without verifying the reference voltage and ground integrity first. Use a scan tool to monitor the sensor's live output; a truly failed sensor shows a stuck, flatlined reading — a sensor that fluctuates but reads slightly off usually indicates a wiring or vacuum issue, not a dead sensor. Always spray electrical contact cleaner on the connector pins before condemning the sensor.
Sensor replacement: $150 - $350