What Does P0718 Mean?
The input/turbine speed sensor A circuit is producing an intermittent signal. The TCM occasionally loses the speed signal and then regains it. This causes momentary confusion in shift scheduling and torque converter clutch control. The driver may feel occasional slipping, flaring, or brief harsh engagements during shifts.
Common Causes
35%
Loose or corroded input speed sensor connector
25%
Failing input speed sensor with intermittent output
20%
Damaged wiring with intermittent breaks under vibration
10%
Reluctor ring partially damaged causing periodic signal dropout
10%
Excessive sensor air gap that causes signal loss at low speeds
Diagnostic Steps
1
Monitor the ISS PID in live data during a road test. Log the data and look for momentary drops to 0 RPM while the vehicle is moving — this confirms intermittent signal loss.
2
Wiggle the sensor connector and harness while monitoring live data. Any correlation between movement and signal dropout pinpoints the issue location.
3
Inspect the connector for corrosion, water, or loose terminals. Check the sensor mounting bolt torque — a loose sensor can vibrate and lose signal contact.
4
If the signal drops only at certain input shaft speeds, suspect reluctor ring damage. This may require transmission disassembly to inspect the tone wheel.
5
Check sensor resistance while tapping and flexing it. Intermittent OL (open) readings confirm an internal sensor fault.
Estimated Repair Cost
$100 - $500
Parts + labor, varies by vehicle and location
The input/turbine speed sensor A circuit is producing an intermittent signal. The TCM occasionally loses the speed signal and then regains it. This causes momentary confusion in shift scheduling and torque converter clutch control. The driver may feel occasional slipping, flaring, or brief harsh eng...
The most common cause of P0718 (Input/Turbine Speed Sensor A Circuit Intermittent) is: Loose or corroded input speed sensor connector
Typical repair costs for P0718 range from $100 to $500, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Intermittent input speed signal loss can cause unexpected shift quality changes while driving. The TCM may briefly flare or slip during signal dropouts. Avoid heavy-load situations and repair soon to prevent potential transmission damage from incorrect shift commands.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P0718 to identify the root cause.
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Quick Info
Category
Powertrain
System
Transmission
Difficulty
Type
Generic (SAE)
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