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P1717 Transmission Input Speed Sensor Intermittent: Complete Technical Guide
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1.0 Understanding Code P1717
Diagnostic Trouble Code (DTC) P1717 indicates an intermittent fault in the Transmission Input Speed Sensor (TISS) circuit. This sensor, also known as the Turbine Shaft Speed Sensor, monitors the rotational speed of the transmission’s input shaft, providing critical data to the Transmission Control Module (TCM) or Powertrain Control Module (PCM) for precise shift timing, torque converter clutch lockup, and transmission pressure control.
An “intermittent” fault means the signal from the sensor drops out momentarily or becomes erratic, but may not be permanently lost. This makes P1717 particularly challenging to diagnose, as the problem may not be present during standard testing.
2.0 Related & Confusing Error Codes
P1717 is part of a family of transmission speed sensor codes. Misdiagnosis is common, so understanding related codes is essential.
| Error Code | Description | Key Difference from P1717 |
|---|---|---|
| P0715 | Input/Turbine Speed Sensor Circuit Malfunction | General circuit fault (open/short). P1717 is specifically intermittent. |
| P0716 | Input/Turbine Speed Sensor Circuit Range/Performance | Signal is implausible or out of expected range. |
| P0717 | Input/Turbine Speed Sensor Circuit No Signal | Complete signal loss, not intermittent. |
| P0720 | Output Speed Sensor Circuit Malfunction | Fault is in the output (post-gears) sensor, not the input. |
| P1713 | Turbine Shaft Speed Sensor Intermittent | Manufacturer-specific variant of P1717 (e.g., some Toyota, Chrysler). |
| P2714 | Pressure Control Solenoid “D” Intermittent | Often co-sets with P1717; a faulty solenoid can mimic sensor issues. |
3.0 Symptoms & Vehicle Behavior
3.1 Primary Symptoms
- Check Engine Light: Illuminates with P1717 stored. May flash during severe misfire events caused by erratic shifting.
- Erratic or Harsh Shifting: The most common symptom. Transmission may slam into gear, shift at wrong RPM, or “hunt” between gears.
- Loss of Torque Converter Clutch (TCC) Lockup: Causes increased RPM at highway speeds, reducing fuel economy.
- Transmission Slipping: Feels like a clutch slip in a manual vehicle; RPM flares during gear changes.
3.2 Vehicle-Specific Patterns
| Vehicle Make/Model | Common Complaint | Typical Mileage |
|---|---|---|
| Ford F-150 (5R55/6R80 Trans) | Harsh 2-3 shift, limp mode | 80,000 – 120,000 mi |
| Toyota Camry (U-series) | Delayed engagement, no lockup | 100,000 – 150,000 mi |
| Chrysler Minivans (62TE) | Flare between 3rd and 4th gear | 60,000 – 90,000 mi |
| GM Trucks (4L60-E) | Code sets when cold, TCC shudder | 70,000 – 110,000 mi |
4.0 Step-by-Step Diagnostic Procedure
Follow this systematic approach to pinpoint the cause of the intermittent fault.
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Preliminary Scan & Data Review
Use an advanced scan tool to monitor Input Shaft RPM (PID: ISS_RPM) and Output Shaft RPM (PID: OSS_RPM) in live data. Drive the vehicle and graph the data, looking for dropouts or erratic ISS readings while OSS remains stable. -
Visual & Physical Inspection (Most Common Fix!)
- Trace the sensor wiring harness from the TISS to the TCM. Look for chafing against hot exhaust, sharp brackets, or the engine block.
- Check the connector at the transmission. Look for corrosion, green/white deposits, or bent pins.
- Inspect the sensor mounting for proper seating and seal. Look for metal debris on the magnetic sensor tip.
-
Circuit Testing (Sensor Unplugged)
With the battery disconnected and sensor unplugged:
While testing, wiggle and heat (with a heat gun) the harness to reproduce the intermittent.Test Procedure Expected Result Reference Voltage Measure between harness connector REF and GND pins. Typically 5V or 12V (check service manual). Ground Circuit Measure resistance between harness GND pin and chassis ground. Less than 5 Ohms. Signal Circuit Check for continuity between harness SIG pin and TCM pin. Continuity, no shorts to power or ground. -
Sensor Bench Test
Measure the sensor’s internal resistance (if magnetic) across its two pins. Compare to manufacturer specs (often 200-1500 Ohms). An active (Hall-effect) sensor requires power to test its square wave output with an oscilloscope. -
Final Verification
Clear codes, perform a complete drive cycle, and re-monitor live data to confirm the intermittent fault is resolved.
5.0 Root Causes & Repair Solutions
5.1 Most Common Causes (75% of Cases)
- Damaged Wiring or Connector (40%): Repair with solder and heat-shrink tubing. Replace damaged connectors entirely.
- Failing Sensor (25%): Internal electronics break down with heat/vibration. Replace with OEM or high-quality aftermarket.
- Poor Electrical Connection (10%): Clean terminals with electrical contact cleaner, apply dielectric grease, and ensure secure latch.
5.2 Less Common but Critical Causes
- Internal Transmission Failure: Excessive bearing play or damaged tone wheel can cause erratic signal.
- Failing TCM/PCM: Rare, but internal fault in the control module can cause intermittent signal processing errors.
- Voltage Supply Issue: A problem in the sensor’s power supply circuit from the TCM.
5.3 Cost Estimation Table
| Repair Action | Parts Cost (Avg.) | Labor Time | Total Estimate |
|---|---|---|---|
| Wiring Harness Repair | $20 – $50 | 0.5 – 1.5 hrs | $100 – $250 |
| Input Speed Sensor Replacement | $80 – $200 | 1.0 – 2.0 hrs | $250 – $500 |
| Transmission Connector Replacement | $30 – $100 | 1.5 – 2.5 hrs | $200 – $400 |
| Complete TCM Replacement | $300 – $800 | 1.0 – 2.0 hrs | $500 – $1,200 |
6.0 Frequently Asked Questions (FAQ)
Not recommended for extended driving. The vehicle will likely be in a fail-safe or “limp” mode, which disables overdrive and torque converter lockup. This causes poor fuel economy, increased transmission heat, and potential further damage from erratic shifting. Drive only to a safe location for repair.
This is the hallmark of an intermittent fault. The root cause (like a broken wire that only loses contact on bumps) wasn’t found. The code will set again once the monitoring system detects the signal dropout during a specific drive cycle (usually 2-3 key cycles). Proper diagnosis requires reproducing the fault.
Yes, they are the same component. “Input Speed Sensor” is the generic SAE term (used in code P0715-P0717). “Turbine Speed Sensor” or “Turbine Shaft Speed Sensor” is a manufacturer-specific name (used in codes like P1713, P1717) referring to the same sensor that reads the speed of the input/turbine shaft.
Typically, no programming is required for just the sensor. However, some modern vehicles (especially after 2015) may require a relearn or adaptation reset using a professional scan tool to clear adaptation values and allow the TCM to relearn the new sensor’s signal characteristics. Always check service information for your specific vehicle.
