P0715 on 2015-2016 Ford Taurus: Input Speed Sensor Circuit Malfunction Guide

What's Unique About the 2015-2016 Ford Taurus

The 2015-2016 Ford Taurus uses the 6F50 or 6F55 six-speed automatic transmission. A key detail for this platform is that it has two primary speed sensors: an Input Speed Sensor (TSS) and an Output Speed Sensor (OSS). Code P0715 specifically points to the TSS, which is fortunately mounted externally on the transmission case. This makes it accessible and replaceable without removing the transmission, a much simpler job than replacing the internal OSS which is associated with different trouble codes (like P0720). The TSS sensor is located on the top of the transmission case.

Symptoms You May Notice

• Harsh, erratic, or delayed gear shifts
• Vehicle enters "limp mode," often getting stuck in 3rd or 5th gear
• Check Engine Light is on
• Reduced fuel economy
• In some cases, the speedometer may malfunction or read incorrectly
• "Transmission Limited Function" warning on the dashboard display
• Vehicle bucks or jerks during shifts
• Banging noise when shifting into gear from a stop

Most Likely Causes

1. Failed Input/Turbine Speed Sensor (TSS) 🔴 High Probability → Shop Automatic Transmission Input Shaft Speed Sensor The sensor is an electronic component exposed to heat and vibration from the transmission, making it a common failure point over time. Intermittent shorts within the sensor are a known issue on this transmission family.
   How to confirm: After checking wiring, test the sensor's resistance with a multimeter to see if it's within the manufacturer's specifications (typically between 500-1,200 Ω). A scan tool can also monitor the sensor's output in real-time; dropouts or erratic readings confirm failure.
   Typical fix: Replace the Input/Turbine Speed Sensor. It is held to the transmission case by a single 8mm bolt.
   Est. part cost: $30-$120
2. Damaged Wiring or Connector 🟡 Medium Probability The wiring harness leading to the sensor can be damaged by road debris, heat from the engine/exhaust, or corrosion, especially at the connector. Chafing or broken strands can disrupt the signal.
   How to confirm: Visually inspect the wiring harness from the TCM to the sensor for any signs of fraying, melting, or breaks. Check the connector for corrosion, bent pins, or a loose fit. Use a multimeter to check for continuity and shorts in the wiring.
   Typical fix: Repair the damaged section of wire or replace the pigtail connector.
   Est. part cost: $15-$40
3. Low or Dirty Transmission Fluid ⚪ Low Probability → Shop Transmission Assembly While not a direct cause of a circuit code, low or contaminated fluid can cause shifting problems and internal component wear. Metal debris suspended in the fluid can accumulate on the magnetic tip of the sensor, disrupting its reading.
   How to confirm: Check the transmission fluid level and condition according to the owner's manual procedure. Fluid should be red and clear, not brown, black, or burnt-smelling. Inspect the sensor tip for metal shavings upon removal.
   Typical fix: Perform a transmission fluid drain-and-fill or a full fluid exchange if the fluid is old or contaminated. Clean any debris from the sensor.
   Est. part cost: $100-$250

Rare But Worth Checking

• Faulty Powertrain Control Module (PCM) or Transmission Control Module (TCM): → Shop Transmission Assembly This is very uncommon. The sensor and wiring should be thoroughly tested before considering the control module as the cause. TSBs for older models specifically advise against replacing the PCM for this code until the sensor has been replaced and the fix verified.
• Internal Transmission Failure: → Shop Transmission Assembly A damaged reluctor ring or other internal mechanical problems can cause this code, but would typically be accompanied by other symptoms like grinding noises or severe slipping.

Diagnosis Steps

1. Scan for Codes: Use an OBD-II scanner to confirm P0715 is the primary code. Note any other transmission-related codes, especially P0717, P0720, P0721, or P0722.
2. Check Transmission Fluid: Verify the transmission fluid level and condition. Low or burnt fluid can indicate larger problems.
3. Inspect Wiring and Connector: Visually inspect the wiring harness leading to the Input/Turbine Speed Sensor. Look for damage, corrosion, or loose connections. The sensor is located on the exterior of the transmission case, near the top.
4. Test the Sensor: If the wiring appears intact, disconnect the sensor and test its internal resistance with a digital multimeter. Compare the reading to the specifications (typically 500-1,200 Ohms). If you have an advanced scan tool, monitor the live data for the input speed RPM while driving; the signal should be smooth and correspond to engine RPM. Any dropouts indicate a faulty sensor.
5. Inspect for Debris: When removing the sensor, check its magnetic tip for excessive metal shavings. A small amount of fine metal dust is normal, but large flakes indicate a more serious internal transmission problem.
6. Replace the Sensor: If the sensor fails the test or is contaminated, replace it. It is typically held in by a single 8mm or 10mm bolt.
7. Clear Codes and Test Drive: After replacement, clear the trouble codes and perform a test drive to ensure the transmission shifts smoothly and the code does not return.

Parts You'll Likely Need

• Transmission Input Speed Sensor / Turbine Speed Sensor (TSS) (OEM #AA5Z-7M101-B) — This sensor is the most common failure point for code P0715 on the 6F50/6F55 transmission.
  Trusted brands: Motorcraft, Standard Motor Products (SMP), NTK
  OEM price range: $80-$120
  Aftermarket price range: $30-$60

Related Codes That Often Appear With This One

• P0717 — P0717 indicates 'No Signal' from the same sensor, which can be triggered alongside P0715 if the signal is intermittent before failing completely.
• P0720 — This code relates to the Output Speed Sensor (OSS). If both input and output sensor codes are present, it may point to a larger wiring harness issue or an internal transmission problem affecting both components.
• P0721 — This code indicates an erratic signal from the Output Speed Sensor (OSS). Seeing it with P0715 could suggest a widespread electrical issue or internal transmission problem.
• P0722 — This code indicates 'No Signal' from the Output Speed Sensor (OSS). Like P0720, its presence with P0715 points towards a potentially larger issue than just the single TSS sensor.

Technical Service Bulletins (TSBs) & Recalls

• TSB 15-0156: The initial pass mentioned this TSB. However, further research shows TSB 15-0156 actually pertains to a vibration or noise from a cracked right-hand halfshaft bearing bracket on vehicles with 2.0L or 2.3L GTDI engines, and is not directly related to code P0715.
• TSB 07-21-11: While for earlier model years (2007-2008) with the 6F50 transmission, this TSB is highly relevant. It addresses DTCs including P0715 caused by an intermittent short in the TSS or OSS sensor, and instructs technicians to replace the sensor before considering a PCM replacement. This establishes a history of this specific failure mode on this transmission family.

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 — Commonly occurs between 60,000 and 120,000 miles. Failure is catastrophic as the pump is driven by the timing chain. When the seal fails, coolant mixes directly with the engine oil, leading to engine failure if not caught immediately.
• Power Transfer Unit (PTU) Overheating and Failure (AWD Models) 🔴 High — Can occur at any mileage, but risk increases without preventative maintenance. The PTU is located next to the hot exhaust, which cooks the 'lifetime' fluid, causing it to break down and leak. Symptoms include a burning gear oil/propane smell, whining/grinding noises, and leaks. (Ref: TSB 19-2017 (for leaks))
• Electronic Throttle Body (ETB) Malfunction 🟠 Medium — Widespread enough to prompt a Customer Satisfaction Program. The ETB can fail, causing the vehicle to enter a low-power 'limp mode' and illuminate the wrench light. (Ref: Customer Satisfaction Program 16B32)
• Cracked Rear Suspension Toe Links 🔴 High — Affects SHO and Police Interceptor models primarily, but included in a recall for other models. The toe link can fracture, causing a sudden loss of steering control. (Ref: Recall 20S04)
• Leaking Turbocharger Oil Supply Tubes (3.5L EcoBoost) 🔴 High — Affects vehicles with the 3.5L GTDI (EcoBoost) engine. Improperly brazed tubes can leak oil onto hot engine components, creating a fire risk. (Ref: Recall 16S46)

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 — Often appears alongside P0715 as it relates to the Input/Turbine Speed Sensor Circuit No Signal.
• P0720 — A companion transmission speed sensor code mentioned in the diagnostic steps for the 6F50/6F55 transmission family.
• P0721 — Related to the Output Speed Sensor (OSS) circuit range/performance, which TSB 07-21-11 identifies as a common failure point alongside the TSS.
• P0722 — Output Speed Sensor Circuit No Signal; frequently scanned and monitored during the same diagnostic procedure as P0715.

Frequently Asked Questions