P0718 Turbine (input) shaft speed sensor signal drops in and out

Turbine shaft speed sensor circuit intermittent

Severity not verified — if the car runs badly, have it inspected

We found no source rating P0718. Ford ties it to harsh engagement, no upshift and fifth-gear-only operation on some transaxles, so it can affect how the car drives.

It gets more serious if:

  • Inspect soon: If the transmission shifts harshly, will not upshift, or stays in one gear, have it inspected soon.

Source: how we rate severity

P0718 in short

P0718 means the signal from the turbine (input) shaft speed sensor is dropping in and out. A loose connector or damaged wiring, the sensor, or the control module can all do it. On some Ford 6F50 transaxles it comes with harsh shifts and stuck gears. Have it scanned soon.

The transmission computer compares the speed of the turbine (input) shaft with engine speed and output speed to decide shift timing and whether the torque converter is slipping. P0718 sets when the turbine speed signal is intermittent, meaning it cuts out or glitches.

TroubleCodes.net lists wiring, a poor connection, the turbine shaft speed sensor and the control module as the probable causes. Ford has a bulletin for 6F50 transaxles built before 1 January 2007 with P0715, P0717, P0718, P0720, harsh engagement, no upshift and fifth gear only.

NHTSA complaints include a 2008 Ford Edge owner quoting that bulletin, and a 2006 Mercedes E350 owner who reports limp mode in first or second gear with P0717 and P0718 and blames the transmission conductor plate. These are owner reports and not a confirmed cause.

Most likely causes

  1. Wiring or a poor connection to the sensor

    Common general cause
    Why it ranks here
    TroubleCodes.net lists wiring and a poor connection first, which fits a signal that cuts in and out rather than one that is dead.
    What would change this
    Rises if wiggling the harness or connector makes the speed signal drop. Falls if the signal is steady and connections are tight.

  2. Failing turbine shaft speed sensor

    Common general cause
    Why it ranks here
    TroubleCodes.net lists the sensor among the probable causes.
    What would change this
    Rises if the sensor signal is erratic with a good harness. Falls if the signal is clean on a scan tool during a road test.

  3. Ford 6F50 transaxle built before 1 January 2007 (some Edge, MKX, Taurus, Sable)

    Supported by vehicle data
    Why it ranks here
    Ford TSB 07-3-11 lists P0718 with harsh engagement, no upshift and fifth gear only on these transaxles. We read only the NHTSA summary, so the repair is not stated here.
    What would change this
    Rises on an Edge, MKX, Taurus, Taurus X or Sable with the build date and symptoms. Falls on any other vehicle.

  4. Transmission computer fault

    Possible — needs testing
    Why it ranks here
    TroubleCodes.net lists the control module. A Mercedes E350 complaint blames the transmission conductor plate for P0717 and P0718, but that is an owner opinion.
    What would change this
    Rises if wiring and the sensor test good. Falls if a wiring or sensor fault is found.
    How to test the transmission control module (tcm)

What to test first

Start at step 1. Each result tells you what it means and where to go next.

  1. Read the stored codes and, on a road test, watch the turbine speed and engine speed on a scan tool for dropouts. Note P0715, P0717 or output speed codes.

    Low riskTool: scan tool with transmission live data

  2. Inspect the sensor connector and harness, then wiggle them with the engine off and again with the engine idling in park while watching the speed signal.

    Use cautionTool: multimeter and scan tool

    Warning:Keep hands and tools clear of belts and the fan with the engine running, and keep the vehicle in park with the parking brake set. Hot exhaust and transmission parts can burn.

Symptoms

  • Check engine light on
  • Harsh gear engagement
  • No upshift, or stuck in one gear (fifth gear only on some Fords) Gets more serious: stop and have it checked.
  • Limp mode in first or second gear Gets more serious: stop and have it checked.
  • Speedometer or shift behaviour that comes and goes

How to fix

  1. With the engine off, check that the transmission speed sensor connector is fully seated and the wiring is not rubbed.

  2. Ask a dealer whether a bulletin applies to your VIN for P0718.

Parts and cost context

  • Transmission control module (TCM):Test the sensor and wiring first. Labour varies; get a quote.

Labor varies by vehicle and shop; get a quote before you approve a repair.

Compare used part prices on PartPriceGuide

On your vehicle

Ford

  • 2007–2008 · Edge

    Supported by vehicle data

    Ford TSB 07-3-11 lists P0718 with harsh engagement, no upshift and fifth gear only on 6F50 transaxles built before 1 January 2007. An NHTSA complaint from a 2008 Edge owner quotes it. Whether the bulletin is still current is not verified.

  • 07311 (ford)Status unverified

    6F50 transaxle built before 1/1/07: P0715, P0717, P0718, P0720, harsh engagement, no upshift

    2007–2008edge, taurus, taurus-x · issued · NHTSA 10021280

    Ford summary lists P0718 with harsh engagement, no upshift and fifth gear only on 6F50 transaxles built before 1 January 2007. The cache summary does not give the repair.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

Lincoln

  • 2007–2008 · MKX

    Supported by vehicle data

    The same Ford bulletin covers 2007-2008 MKX with a 6F50 transaxle built before 1 January 2007. Whether the bulletin is still current is not verified.

  • 07311 (lincoln)Status unverified

    6F50 transaxle built before 1/1/07: P0715, P0717, P0718, P0720, harsh engagement, no upshift

    2007–2008mkx · issued · NHTSA 10021280

    Same Ford bulletin for the MKX: P0718 with harsh engagement, no upshift and fifth gear only. The summary does not give the repair.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

Mercury

  • 2008 · Sable

    Supported by vehicle data

    The same Ford bulletin covers the 2008 Sable with a 6F50 transaxle built before 1 January 2007. Whether the bulletin is still current is not verified.

  • 07311 (mercury)Status unverified

    6F50 transaxle built before 1/1/07: P0715, P0717, P0718, P0720, harsh engagement, no upshift

    2008sable · issued · NHTSA 10021280

    Same Ford bulletin for the Sable: P0718 with harsh engagement, no upshift and fifth gear only. The summary does not give the repair.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

Mercedes-Benz

  • 2006 · E-Class

    Possible — needs testing

    An NHTSA complaint on a 2006 E350 reports limp mode in first or second gear with P0717 and P0718 and blames the transmission conductor plate. Owner opinion; no cause was confirmed.

  • P0715Transmission input or turbine shaft speed sensor circuit fault

    Same system Supported by vehicle data

    Ford bulletin 07-3-11 lists P0715, P0717 and P0718 together.

  • P0717No signal from the transmission input or turbine speed sensor

    Same system Supported by vehicle data

    Ford bulletin 07-3-11 and a Mercedes E350 complaint list P0717 with P0718: no signal as well as intermittent.

  • P0720Transmission output shaft speed sensor circuit fault

    Same system Supported by vehicle data

    Ford TSB 07-3-11 lists the output speed sensor code P0720 with P0718.

All Transmission codes

P0718 questions

What does P0718 mean?

The turbine (input) shaft speed sensor signal is intermittent, meaning it drops out or glitches.

What is the difference between P0717 and P0718?

P0717 means the signal is missing, while P0718 means it comes and goes. Both involve the same sensor and circuit.

Sources and review

  1. Ford TSB 07-3-11 (NHTSA 10021280) — Ford Motor Company ,
  2. NHTSA complaint 10956957: 2006 Mercedes-Benz E350 — NHTSA Office of Defects Investigation
  3. P0718 - Turbine shaft speed sensor - circuit intermittent — TroubleCodes.net
  4. NHTSA complaint 10692963: 2008 Ford Edge — NHTSA Office of Defects Investigation
Last reviewed
Written by
Saurabh K.
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