P0717
PowertrainInput/Turbine Speed Sensor Circuit No Signal
This can swing from a cheap afternoon job to a gearbox-out nightmare, so don't panic until you've checked the basics. The transmission control module relies on the input speed sensor to tell it how fast the gearbox input shaft is spinning. With P0717 it's getting nothing at all, no signal whatsoever, which is usually a sensor or wiring fault but can occasionally point to something nasty inside the box. The car often drops into limp mode to protect itself while this code is live.
ⓘ Information only. This page provides general educational information about fault code P0717. We do not assess the urgency or safety implications of any specific fault. That requires in-person diagnosis by a qualified mechanic. Full terms.
Recommended next steps
Whether a fault is urgent, drivable, or routine depends entirely on the cause on a specific vehicle, and that can only be determined by a qualified mechanic with diagnostic equipment. If a warning light is illuminated, the most reliable next step is professional diagnosis.
What does P0717 mean?
P0717 is a Powertrain (engine, transmission, fuel system) fault code. It indicates: Input/Turbine Speed Sensor Circuit No Signal.
This is a standardised OBD-II code. The technical definition is the same regardless of the make or model of vehicle, although specific causes and symptoms can vary between vehicles.
Symptoms commonly associated with this code
Symptoms that drivers often report alongside this code. Not all may apply to every case:
- • Engine warning light on, sometimes with a gearbox warning symbol as well
- • Gearbox stuck in one gear, commonly second or third, so it feels gutless and revs high on the motorway
- • Harsh or delayed shifts, especially the first few changes when pulling away
- • Car hesitating or feeling like it wants to stall as you come to a stop
- • Fuel economy drops off because it's holding the wrong gear
- • Odd clunks or a refusal to engage cleanly when you select reverse
Possible causes
Causes commonly associated with P0717, listed in approximate order of typical investigation. The actual cause on a specific vehicle can only be confirmed by professional diagnosis.
- 1. Failed input speed sensor, the usual culprit. The pickup or its internal coil packs in and the signal vanishes completely
- 2. Damaged or corroded wiring between the sensor and the TCM. Heat and road salt do a number on these looms over the years
- 3. Loose or dirty connector at the sensor. A bad pin contact gives the exact same no-signal reading as a dead sensor
- 4. Low or burnt automatic transmission fluid. If the fluid level has dropped or it's gone dark and smells cooked, sort that first
- 5. Metal swarf from internal wear clinging to the sensor tip and blocking the pickup. This one tells you the box is wearing
- 6. Internal damage to the reluctor ring or input shaft, less common but it does happen on high-mileage autos
- 7. Faulty transmission control module itself, rare, and you rule this out last not first
How mechanics typically diagnose
A typical diagnostic sequence used by mechanics, provided here for educational reference only. Diagnostic work should be performed by a qualified mechanic with the appropriate tools and training.
- 1. Read the codes and the freeze-frame data, then note whether P0717 is sitting alongside other gearbox codes like P0700 or fluid temperature faults. The full picture matters here
- 2. Get under the car and inspect the sensor connector and the loom running to it. Look for green corrosion, chafed insulation, and connectors that pull apart with no resistance
- 3. Check the transmission fluid level and condition with the engine warm. Low or contaminated fluid throws all sorts of sensor faults and is the cheapest thing to fix
- 4. Ohm out the sensor against the manufacturer's spec figure. Most of these read in the few hundred to low thousands of ohms range, but check the actual value for your model
- 5. Watch the input speed sensor live data on a scan tool during a short test drive. If it stays flat at zero while the engine is clearly turning the box, you've confirmed no signal
- 6. If wiring and sensor both check out, look up any technical service bulletins for your model and only then move on to testing the TCM
Common questions about P0717
Should I save money and fit a pattern sensor, or pay for the genuine one? +
For the speed sensor itself, a decent quality aftermarket part from a known brand is usually fine and will save you a fair bit over the dealer price. Where I'd spend the extra is on certain ZF and Aisin boxes, plus a lot of VAG DSG units, where the sensor is part of an internal mechatronic assembly and the cheap eBay copies are hit and miss. If your sensor is a standalone bolt-in pickup, pattern is fine. If it's buried in the valve body, buy the proper part and fit it once.
Is it actually safe to keep driving like this? +
I wouldn't make a habit of it. With no input speed signal the gearbox often locks into one gear and shifts become unpredictable, which is exactly what you don't want when you're pulling out of a junction or joining a motorway. A gentle drive straight home or to the garage is one thing. Daily commuting on it risks both your safety and cooking the transmission if it's running in limp mode for weeks. Get it looked at sooner rather than later.
Will this cause me to fail the MOT? +
There's no gearbox shift test in the MOT, so P0717 on its own isn't a direct fail. The catch is the warning light. If the engine management lamp is glowing on the dash when the tester walks up to the car, that's a fail on its own under the current rules regardless of what the code is. Fix the cause, clear the code, and let the light stay off through a couple of drive cycles before you book the test.
Information only, not professional advice
The information on this page is provided for general guidance and educational purposes only. It is not a substitute for diagnosis or repair advice from a qualified mechanic. Always verify any fault before paying for repairs. carfaultcodes.co.uk accepts no liability for decisions made based on this information. Full terms →