P0715 on 2008 Ford Taurus: Input/Turbine Speed Sensor Failure Causes and Fixes

What's Unique About the 2008-2008 Ford Taurus

The 2008 Ford Taurus uses the 6F50 automatic transmission, a unit shared with many other Ford, Lincoln, and Mercury vehicles. Ford issued a Technical Service Bulletin (TSB 07-21-11) for this specific transmission in the 2008 Taurus (and other models) for P0715 and related codes. The TSB notes that vehicles with a transaxle build date before October 21, 2007, could have an intermittent short in the Turbine Shaft Speed (TSS) sensor, making sensor failure a very common and documented issue on this platform. The TSS sensor is located internally, behind the transmission's side cover, making replacement more labor-intensive than an externally mounted sensor.

Symptoms You May Notice

• Harsh or erratic shifting
• Transmission stuck in one gear (fail-safe mode)
• Failure to upshift
• Check Engine Light is on
• Decreased fuel economy
• Wrench light (powertrain fault) may illuminate on the dashboard
• Vehicle may feel like it's in neutral while in gear

Most Likely Causes

1. Faulty Turbine Shaft Speed (TSS) Sensor 🔴 High Probability Ford TSB 07-21-11 specifically identifies an intermittent short in the TSS sensor as a known issue on 6F50 transmissions built before 10/21/2007. The sensor is submerged in hot transmission fluid, which can degrade the internal electronics over time.
   How to confirm: Follow the diagnostic pinpoint test outlined in the factory service manual or TSB. This typically involves checking the sensor's signal with a scan tool and testing its resistance with a multimeter. A scan tool showing an erratic or zero RPM reading for the input/turbine speed while the vehicle is moving confirms a sensor circuit issue.
   Typical fix: Replace the Turbine Shaft Speed (TSS) sensor. The TSS sensor is located in the end cover of the transmission. Because accessing it requires significant labor, it is highly recommended to also replace the Output Shaft Speed (OSS) sensor at the same time, as they are located in the same area. 🎬 See how to remove and install 6F50 TSS and OSS sensors
   Est. part cost: $35-$75
2. Damaged Wiring or Connectors 🟡 Medium Probability
   How to confirm: Visually inspect the wiring harness leading to the transmission for any signs of fraying, corrosion, or damage. Check for a secure connection at the main transmission bulkhead connector. Test for continuity and resistance on the wires between the PCM/TCM and the transmission connector.
   Typical fix: Repair or replace the damaged section of the wiring harness or the connector.
   Est. part cost: $10-$50
3. Dirty or Low Transmission Fluid ⚪ Low Probability
   How to confirm: Check the transmission fluid level and condition. Fluid that is dark, burnt-smelling, or contains excessive metal shavings can indicate internal problems and interfere with sensor operation.
   Typical fix: Perform a transmission fluid and filter change. If significant debris is found, further internal inspection is needed.
   Est. part cost: $100-$250

Rare But Worth Checking

• Faulty Powertrain Control Module (PCM): This is a rare cause. The TSB specifically advises against replacing the PCM until the sensor has been confirmed as the root cause. All other possibilities, especially the sensor and wiring, should be exhausted first.
• Internal Transmission Failure: Mechanical issues like a damaged reluctor ring or other internal transmission problems can trigger this code, but would typically be accompanied by more severe mechanical symptoms.

Diagnosis Steps

1. Connect a scan tool and verify that P0715 is the active code. Check for any other related transmission codes.
2. Check the transmission build date. If it is before 10/21/2007, refer to TSB 07-21-11 as the primary diagnostic path.
3. Using a scan tool with live data capability, monitor the Input/Turbine Speed Sensor (TSS) PID. Check for an erratic or non-existent signal while driving. The reading should correspond with engine RPM.
4. Visually inspect the external transmission wiring harness and main connector for any obvious damage, corrosion, or loose connections.
5. If wiring appears okay, test the sensor's internal resistance with a digital multimeter at the transmission connector pins and compare it to the manufacturer's specifications (typically 500-1,200 Ω).
6. If the sensor tests faulty or if the TSB applies, replace the Turbine Shaft Speed (TSS) sensor. It is highly recommended to replace the Output Shaft Speed (OSS) sensor at the same time.
7. If the sensor and wiring are good, check the condition and level of the transmission fluid.
8. If the problem persists, more advanced diagnostics of the PCM or internal transmission components may be required.

Parts You'll Likely Need

• Turbine Shaft Speed (TSS) Sensor (OEM #8A8Z-7M101-A) — This is the most common failure point for a P0715 code on this vehicle, as identified by a specific Ford TSB. This part number has been superseded by AA5Z-7M101-B.
  Trusted brands: Motorcraft, Standard Motor Products (SMP), NTK
  OEM price range: $50-$90
  Aftermarket price range: $35-$75
• Output Shaft Speed (OSS) Sensor (OEM #8A8Z-7H103-A) — Recommended to be replaced at the same time as the TSS sensor due to identical labor required for access. It is also a common failure point addressed in the same TSB.
  Trusted brands: Motorcraft, Standard Motor Products (SMP), Dorman
  OEM price range: $40-$80
  Aftermarket price range: $30-$60

Related Codes That Often Appear With This One

• P0717 — This code indicates 'Input/Turbine Speed Sensor A Circuit No Signal,' which is a more specific version of the P0715 fault, often pointing directly to a dead sensor or complete wiring break.
• P0718 — This code means 'Input/Turbine Speed Sensor A Circuit Intermittent,' which strongly aligns with the intermittent short described in the Ford TSB.
• P0720 — This code relates to the Output Shaft Speed (OSS) sensor. The TSB for the 6F50 transmission groups TSS and OSS sensor codes together, as they can have similar root causes and are often replaced at the same time due to their internal location.
• P0722 — This code indicates 'Output Speed Sensor Circuit No Signal.' It is frequently seen with the TSS codes and is also covered by TSB 07-21-11, pointing to a related internal sensor failure.

Technical Service Bulletins (TSBs) & Recalls

• TSB 07-21-11: Addresses DTCs P0715, P0717, P0718, P0720, P0721, P0722 and/or harsh engagement, no upshift, or fifth gear only operation on 6F50 transaxles due to a potential intermittent short in the OSS or TSS sensor.

Platform-Specific Known Issues

• TSB 07-21-11 was issued by Ford for 2008 Taurus models with the 6F50 transmission built before 10/21/2007. It directly addresses DTC P0715 caused by an intermittent short in the Turbine Shaft Speed (TSS) sensor.
• The location of the TSS and OSS sensors is internal to the transmission, behind the side cover. This makes replacement a significantly more involved job than on transmissions with external sensors, requiring draining the fluid and removing the cover and valve body.
🎬 Watch this complete walkthrough of the repair, symptoms, and codes

Diagnostic Flowchart

Other Known Issues on This Vehicle

Issues unrelated to this code that are worth knowing about as an owner of this generation:

• Internal Water Pump Failure (3.5L V6) 🔴 High — Common issue, often occurring around 100,000 miles. Failure can cause coolant to mix with engine oil, leading to catastrophic engine damage. (Ref: A class-action lawsuit was filed regarding this issue.)
• Electronic Throttle Body Failure 🔴 High — Widespread failure causing sudden 'limp mode' and loss of acceleration. A very common problem for this engine. (Ref: Ford Customer Satisfaction Program 13N03 (expired) extended the warranty on this part.)
• Leaking Power Steering Hoses 🟠 Medium — The high-pressure power steering hose is prone to leaking, particularly at the crimped ferrules. This can lead to loss of power steering assist and is a potential fire hazard.
• Takata Airbag Recall 🔴 High — The 2008 Taurus was included in the massive Takata airbag recall. The driver's frontal airbag inflator could rupture, causing serious injury or death. (Ref: NHTSA Recall 16V384)

Real Owner Stories

Aggregated from forums and TSBs cited above. Mileages and costs reflect what owners reported in those sources.

Related OBD-II Codes

• P0717 — Identified in TSB 07-21-11 as a related code caused by an intermittent short in the TSS or OSS sensor on 6F50 transmissions.
• P0718 — Identified in TSB 07-21-11 as a related code caused by an intermittent short in the TSS or OSS sensor on 6F50 transmissions.
• P0720 — Related output shaft speed (OSS) sensor code mentioned in TSB 07-21-11; the OSS is located in the same area as the TSS sensor.
• P0721 — Related output shaft speed (OSS) sensor code mentioned in TSB 07-21-11; often diagnosed alongside P0715.
• P0722 — Related output shaft speed (OSS) sensor code mentioned in TSB 07-21-11; often diagnosed alongside P0715.

Frequently Asked Questions