Powertrain, generic · Transmission

P0718 Input/Turbine Shaft Speed Sensor A Circuit Intermittent

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

The input or turbine shaft speed sensor – a Hall sensor with square-wave output or an inductive sensor with sine output – reports the speed behind the torque converter. With output and engine speed it gives the actual gear ratio, converter slip and shift timing. P0718 means the signal is present but jumps or drops out briefly. Ford's petrol modules from 2012 to 2023 count 200 turbine speed spikes above 400 rpm with at most 1.5 s between them in a forward gear. GM's Honda-built five-speed of 2006 flags jumps of more than 3 mph per 10 ms three times in 500 ms, after two trips; GM's own transmissions file such jumps under P0716 instead. Loose contacts and electrical interference are the usual causes; shifts become erratic and limp mode may follow at times.

Likely causes

Loose contact, corroded connector or chafing
Electrical interference (shielding, ground, added consumers)
Metal debris on the sensor or loose mounting
Sensor faulty internally (temperature-dependent)

Symptoms

  • Occasional harsh or unexpected shifts
  • Warning lamp
  • Converter clutch applies and releases unevenly
  • Limp mode at times

Repair estimate

DifficultyMediumDIY possible
Parts and labour€80–450
Time0.5–2.5 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

input speed sensorsensor wiringtransmission control module

Related codes

P0715P0716P0717P0723

References: newtonnet.co.uk, fordservicecontent.com, gsi.ext.gm.com, roushcleantech.com.