P0717

Input/Turbine Speed Sensor A Circuit No Signal

P0717 is a generic OBD-II powertrain diagnostic trouble code: Input/Turbine Speed Sensor A Circuit No Signal. It is logged by the engine control unit when the powertrain monitor detects that a specific fault threshold has been exceeded — typically resulting in the malfunction-indicator lamp (MIL / check-engine light) being illuminated.

Code
P0717
Group
Powertrain
System
Powertrain
Severity
high
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What P0717 means

P0717 is set when the PCM or TCM receives no signal from the input shaft (turbine) speed sensor 'A' under conditions where a signal is expected. The input shaft speed sensor monitors the rotational speed of the transmission's input shaft — which is the turbine side of the torque converter and turns at the same speed as the converter output. This signal is essential for the TCM to calculate the torque converter slip ratio, determine the correct shift point, manage TCC lockup, and adapt line pressure to actual load conditions.

The sensor is typically a variable-reluctance (VR) or Hall-effect type mounted near a tone wheel on the input shaft inside the transmission. VR sensors generate an AC voltage whose frequency and amplitude vary with shaft speed, while Hall-effect sensors output a digital pulse train. Both types go completely silent when the shaft stops, so the TCM must use contextual data (vehicle speed, throttle position, engine RPM) to determine whether a missing signal is normal (vehicle stationary) or a fault (vehicle moving with no sensor output). P0717 is triggered in the latter condition.

The most common cause is a failed sensor, but wiring faults are nearly as frequent — the sensor harness runs through a mechanically stressed environment inside or on the transmission bell housing, and chafing against the housing or flex over time causes intermittent or complete open circuits. Metal debris from worn transmission components can also contaminate the sensor tip's magnetic pickup area and reduce signal amplitude below the TCM's detection threshold. Low or dirty ATF can compromise sensor operation in some designs.

Because the TCM cannot determine gear ratios or TCC slip without the input speed signal, P0717 almost always triggers transmission limp mode. Prompt diagnosis is important — continued operation in limp mode with an unknown root cause can mask an underlying mechanical issue contributing to the sensor failure.

Common causes

Most-frequently reported root causes when P0717 is logged.

  • 1
    Faulty or failed input/turbine speed sensor (internal coil or Hall element failure)
  • 2
    Open circuit or short in the sensor wiring harness
  • 3
    Corroded, damaged, or backed-out connector pins at the sensor or TCM
  • 4
    Metal debris accumulation on the sensor magnetic pickup tip
  • 5
    Damaged or missing tone wheel teeth on the input shaft
  • 6
    Low or contaminated ATF affecting sensor signal amplitude (VR type)
  • 7
    Sensor mounting loose or sensor tip too far from tone wheel
  • 8
    Internal TCM fault misinterpreting the sensor signal

Symptoms drivers notice

Check Engine Light and/or Transmission Warning Light illuminated
Transmission locked in limp mode (typically 2nd or 3rd gear only)
No torque converter clutch (TCC) lockup engagement
Harsh or unpredictable upshifts and downshifts
Engine stall or stumble at idle when coming to a stop
Speedometer reading erratic if input speed is cross-referenced for VSS
Transmission slip at highway speed

How to diagnose P0717

A typical diagnostic flow when this code is present.

  1. 1
    Connect a scan tool and retrieve all DTCs; note any related output speed sensor codes (P0722), TCC codes, or gear ratio codes that may indicate mechanical involvement
  2. 2
    Monitor the input speed sensor PID on a live data stream during a test drive; the value should mirror engine RPM closely when the TCC is unlocked and drop slightly when locked
  3. 3
    With the ignition off, measure sensor resistance (VR type: typically 200–900 Ω depending on manufacturer) or supply voltage and signal output (Hall type) at the sensor connector
  4. 4
    Inspect the sensor harness from the transmission connector to the TCM for chafing, cuts, pinching, or contact with hot or moving components
  5. 5
    Remove the sensor and inspect its tip and the tone wheel for metal debris, damage, or missing teeth; clean the sensor tip with a clean cloth
  6. 6
    Check sensor-to-tone-wheel air gap if serviceable (compare to manufacturer specification, typically 0.5–1.5 mm)
  7. 7
    If sensor and wiring test good, perform a transmission fluid change and inspect drained fluid for excess metallic particles indicating internal wear
  8. 8
    Replace the sensor if confirmed faulty, clear codes, and verify normal live data before returning the vehicle

Related powertrain codes

Frequently asked questions

Will P0717 cause the transmission to stop shifting entirely?

Most TCMs respond by entering limp mode, which restricts the transmission to one or two fixed forward gears to protect drivability. Full shifting is restored once the fault is corrected and codes are cleared.

Can I drive with P0717?

Short distances in limp mode may be necessary to reach a workshop, but extended driving is not advisable. The TCM is operating without accurate torque converter slip data, which can lead to TCC damage and accelerated clutch wear.

How is P0717 different from P0715?

P0715 indicates a general circuit malfunction (signal present but out of range or erratic), while P0717 specifically means no signal is detected at all under conditions where one is expected. P0717 typically points to a complete open circuit or total sensor failure.

Can metal shavings in the ATF cause P0717?

Yes. Ferromagnetic debris from worn transmission components can accumulate on the sensor's magnetic tip, increasing the effective air gap and reducing signal amplitude until the TCM can no longer detect pulses. Finding excessive metallic debris is also a warning sign of transmission mechanical damage.

Disabling P0717 in software

RaceTune can permanently disable P0717 — and any other OBD-II diagnostic trouble code — on every ECU family we support. The monitor is disabled inside the ECU itself, so the fault stops being logged: the warning light stays off and the engine never enters limp mode for this code. The change is tied to your exact software version.

Permanent
The monitor is disabled in the ECU itself — not just cleared. It cannot return.
Tailored to your file
Each patch is matched to your specific software version — never a one-size-fits-all file.
Reversible
The original file is always preserved. Reflash the stock to return the ECU to factory state.

Software modifications affect emissions compliance and are not road-legal in many jurisdictions. RaceTune service files are intended for motorsport, off-road, and export use.

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