P0717 Code: Input/Turbine Speed Sensor A Circuit No Signal
The input speed sensor reports zero while the engine runs and the car moves – the signal is completely gone.
At a glance
Severity: Moderate
- Meaning
- Input/Turbine Speed Sensor A Circuit No Signal
- System
- Transmission · Powertrain
- Safe to drive?
- With caution
- Typical repair cost
- $60–$2,500
- DIY difficulty
- Moderate
P0717 is the clearest of the input speed codes: the module sees no pulses at all from the input or turbine speed sensor, even though engine speed and output speed prove the transmission is turning. A dead signal usually means an open circuit – a broken wire, an unplugged or pushed-out terminal, a sensor coil that has broken internally – or, on three-wire Hall sensors, a missing supply voltage. The transmission normally goes straight into limp mode because it can no longer judge shifts. Where the sensor is built into a conductor plate or mechatronic unit, the whole assembly is usually what gets replaced.
Can I keep driving? Expect limp mode – a single gear, slow acceleration and hard engagement. Drive only as far as needed at moderate speed, without towing, and don't use the highway if the car won't pull above one gear.
How to read P0717
- P Powertrain
- 0 Generic (SAE)
- 7 Transmission
- 17 Specific fault
Symptoms
- Immediate limp mode, usually a fixed higher gear from a standstill
- Sluggish take-off because the car starts in 2nd or 3rd
- Hard clunk when selecting Drive or Reverse
- Input speed shows 0 rpm on the scan tool while the engine idles
- Other speed sensor codes too if a shared supply is missing
- Check engine light, often with P0700
Possible causes
Ranked by how often each cause is behind this code (editorial estimate).
- Sensor internally open (broken coil or dead Hall element)
- Connector unplugged, pushed-out terminal or broken wire
- Sensor inside conductor plate or mechatronic failed
- No supply voltage for a Hall sensor (fuse or shared reference)
- Transmission module input fault
- Sensor tip broken off or target ring damaged
Diagnosis step by step
Confirm zero input speed
At idle in Park or Neutral, check the input speed PID. A flat 0 rpm while output speed reads normally when moving confirms that the input signal is completely missing rather than erratic.
Tools: OBD-II scanner
Check for a recent repair
Ask whether the transmission, engine mounts or battery tray were recently worked on. A connector left unplugged or a harness trapped during reassembly is a common and cheap cause.
Tools: Flashlight
Measure the sensor for an open
On a two-wire magnetic sensor, an infinite resistance reading across the pins means the coil is open and the sensor is dead. Also check each pin to case ground – there should be no continuity.
Tools: Multimeter
Check supply and ground on Hall sensors
With the key on and the connector unplugged, measure the supply pin to ground (typically 5 V or 12 V) and verify the ground pin. If the output speed sensor also has no signal, look first at a shared fuse or reference feed.
Tools: Multimeter
Test the wire back to the module
Check each sensor wire end to end for continuity – under about 1 ohm is normal. An open wire is usually found where the harness flexes near the transmission mount or passes over the case.
Tools: Multimeter
Where the parts are
- 1Battery
- 2Alternator
- 3Engine computer (ECM)
- 4CAN bus
- 5Transmission
- 6Wheel speed sensor
- 7High-voltage battery
Repair options & costs
| Repair | DIY? | Estimated cost |
|---|---|---|
| Reconnect or repair connector and terminals | Yes | $60–$200 |
| Repair open wire in the harness | No | $120–$300 |
| Replace external input speed sensor | Yes | $150–$380 |
| Replace conductor plate or mechatronic unit | No | $900–$2,500 |
Rough US estimates for parts and labor; shop rates vary by region. Not a quote.
Notes by brand
Mercedes-Benz
On Mercedes seven-speed automatics (7G-Tronic, 722.9), the input and output speed sensors are mounted on the conductor plate inside the valve body assembly. Failure of this plate is well known and leads to missing speed signals and limp mode; repair means replacing and coding the conductor plate or control unit, not a single sensor.
Field data
| Nissan | 11 | Pathfinder, Frontier King Cab, Xterra | |
|---|---|---|---|
| Ford | 5 | Edge, Expedition, F-150 CREW CAB | |
| Chevrolet | 4 | Equinox, Malibu, Silverado 1500 | |
| Honda | 4 | Accord, Fit, Hr-V | |
| Dodge | 3 | Caliber | |
| GMC | 2 | Acadia | |
| Hyundai | 2 | Sonata Hybrid, Sonata Plug-In | |
| Mercedes-Benz | 2 | C-Class, E-Class |
Source: NHTSA Complaints API (US government open data), analyzed by DTC mention.
Emissions / smog test impact
Will fail
P0717 keeps the check engine light on and fails an OBD emissions test. Once repaired, the light must stay off and readiness monitors should be complete before retesting.
Frequently asked questions
Why is my car stuck in one gear with P0717?
Without input speed the module can't control shift timing or pressure safely, so it locks the transmission into a fixed limp gear. That prevents damage but makes the car slow off the line.
Could a blown fuse cause P0717?
On transmissions with Hall-type sensors, yes. They need a supply voltage; if the fuse or the shared reference is lost, the sensor has no power and produces no signal. Output speed codes often appear at the same time.
Is the sensor always the culprit?
No. A connector left off after other repairs or a broken wire is almost as common. Checking the circuit before buying a sensor avoids replacing a good part.
What if the sensor is inside the transmission?
Then a shop has to remove the pan or valve body, and on some models replace a whole conductor plate or mechatronic unit and code it. Costs are much higher than for an external sensor.