English-first OBD-II diagnostics Static, fast, focused lookup pages
CD CheckDTC Garage-grade fault lookup
Browse codes Try AI Diagnose
Home / Codes / P0718
DTC code page

P0718: Input/Turbine Speed Sensor Circuit Intermittent

Quick answer: The turbine-speed sensor signal drops out occasionally instead of failing all the time.

Drivers also search this fault as input speed sensor intermittent, turbine speed sensor intermittent, P0718 transmission speed signal dropout.

Severity: high Family: powertrain Related paths: 9
Meaning

What P0718 usually means

P0718 means the transmission controller loses the input or turbine speed signal intermittently. Unlike P0717, where the signal is simply gone, P0718 often creates a more confusing complaint: the car may shift fine on one drive, then flare, bang, or fall into limp mode on another when the input-speed data disappears at the wrong moment. Since the TCM uses that signal for ratio calculation and shift timing, even brief dropouts can make an otherwise healthy transmission feel broken.

Fast triage

Start here before chasing parts

  • Scan first: save freeze-frame and pending codes before clearing anything.
  • Confirm the complaint: compare the stored code with current drivability symptoms.
  • Use context: trims, live data, and related codes usually narrow the fault faster than guesswork.
  • Work simplest to hardest: leaks, connectors, maintenance items, and known patterns before expensive components.
Initial checks

What to check first

  • Review freeze-frame to see whether the dropout happens at startup, during upshifts, or only after warm-up.
  • Compare input-speed PID behavior against engine RPM and output speed for sudden dropouts.
  • Inspect the transmission connector and harness before blaming internal clutches.
Driving risk

Can you keep driving?

An active P0718 can trigger harsh or unpredictable shifts without warning, so diagnose it quickly and avoid long trips until the signal is stable.

High urgency: If symptoms are active, reduce driving and diagnose quickly before secondary damage builds.
Likely causes

Common causes behind this code

  • Intermittently failing input/turbine speed sensor
  • Internal transmission harness or external connector dropout
  • Heat-sensitive wiring or sensor failure
  • Metal debris or fluid contamination affecting the sensor area
  • Loose case connector losing signal over vibration

Cause phrases often tied to this code: intermittent speed sensor, internal harness, connector dropout, signal loss with heat.

Diagnostic order

Suggested workflow

  1. Monitor input-speed data during a road test and look for irrational dropouts or flatlines.
  2. Wiggle-test the connector and harness if the signal changes with movement.
  3. Inspect for fluid intrusion, pin drag, or known internal-harness issues for that transmission family.
  4. Replace the failed sensor or repair the harness only after confirming the signal path is the problem.
  5. Verify that shift timing and limp-mode behavior normalize on a repeat road test.
Avoid guesswork

Common mistakes

  • Jumping straight to transmission replacement because the complaint is intermittent and dramatic.
  • Ignoring live data and diagnosing only from driver description when this code is specifically about signal dropout.
Repair path

Practical fix guidance

  • Restore a stable input-speed signal before making any conclusions about ratio or internal-slip codes that appear alongside it.
  • After repair, retest under the same heat and load conditions that originally triggered the dropout.
Vehicle context

Affected brands in this MVP

Brand hubs help broaden internal linking now and can evolve into make-specific diagnostic notes later.

Aliases and common searches

English phrases tied to P0718

Useful when the driver knows the wording but not the exact DTC yet.

  • input speed sensor intermittent
  • turbine speed sensor intermittent
  • P0718 transmission speed signal dropout
Related search intent

Queries this page can answer naturally

  • P0718 code meaning
  • what does P0718 mean
  • intermittent turbine speed sensor fault
FAQ

Quick questions about P0718

How is P0718 different from P0717?

P0717 means the input-speed signal is essentially gone, while P0718 means it drops out intermittently and may look normal at other times.