What Is Car Fault Code P0718? Diagnose & Clear It with iCarsoft CR Pro S
If your check engine or transmission warning light illuminates and your diagnostic tool retrieves P0718, you’re facing an issue with your vehicle’s Transmission Fluid Temperature (TFT) Sensor Circuit—specifically an “intermittent” or “erratic” signal malfunction. The TFT sensor monitors transmission fluid temperature to optimize shift timing, fluid pressure, and cooling system operation. Ignoring P0718 can lead to harsh shifting, reduced transmission efficiency, overheating, or even transmission damage. In this guide, we’ll break down what P0718 means, why it occurs, and how the iCarsoft CR Pro S—your all-in-one diagnostic solution—can help you resolve it efficiently.
iCarsoft CR Pro S testing TFT sensor circuit & transmission fluid temperature to diagnose P0718 fault code
What Exactly Is Fault Code P0718?
P0718 is a generic OBD-II trouble code defined as “Transmission Fluid Temperature Sensor Circuit Intermittent/Erratic”. The TFT sensor sends temperature data to the Transmission Control Module (TCM) or ECU (Engine Control Unit). When the control unit detects inconsistent, intermittent, or untrustworthy voltage signals from the sensor circuit—outside the normal operating range—it triggers P0718, indicating a sensor, wiring, or module communication issue.
This code applies to vehicles with automatic transmissions (gasoline, diesel, or hybrid). Left unaddressed, it may cause the TCM to default to a “limp mode” to protect the transmission, limiting vehicle speed and performance.
Why Does P0718 Happen? Common Causes
P0718 typically stems from issues with the TFT sensor, its circuit, or related components:
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Faulty TFT Sensor: Internal electrical failure or contamination (e.g., fluid debris) causes erratic temperature readings.
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Wiring/Connector Issues: Damaged, frayed, or shorted wires, or loose/corroded connectors between the sensor and TCM/ECU.
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Low/Contaminated Transmission Fluid: Insufficient or degraded fluid disrupts sensor contact and signal transmission.
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TCM/ECU Malfunction: Rarely, the control module fails to interpret the sensor’s signal correctly.
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Sensor Short/Open Circuit: Intermittent breaks or shorts in the sensor circuit lead to inconsistent voltage.
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Damaged Transmission Housing: Physical damage near the sensor mounting point disrupts sensor alignment or wiring.
Why the iCarsoft CR Pro S Is Ideal for P0718
When it comes to diagnosing and fixing P0718, the iCarsoft CR Pro S outperforms basic scanners by offering deep transmission system insights and global compatibility. Here’s why it’s your best tool:
Full Transmission System Scans
Unlike basic scanners that only read the code, the CR Pro S dives into the TFT sensor circuit, TCM communication, and transmission fluid-related data.
Live Data Monitoring
View real-time TFT sensor voltage, transmission fluid temperature readings, and TCM status to verify erratic signals.
Bi-directional Control
Test the TFT sensor circuit and TCM communication to rule out module vs. sensor/wiring faults—no disassembly needed.
Global Vehicle Support
Works with over 60 makes (Ford, Toyota, BMW, Mercedes-Benz, VW, etc.)—compatible with most automatic transmission-equipped vehicles.
Transmission System Focus
Covers transmission-specific diagnostic functions, including TCM coding and adaptation resets (where applicable).
One-Click Code Clear
After fixing the issue, erase P0718 and turn off warning lights in seconds.
Lifetime Free Updates
Stay compatible with new transmission technologies and sensor designs via Wi-Fi.
Feedback Function
Get customized repair suggestions from certified professionals tailored to your car’s make and model.
How to Diagnose & Fix P0718 with the CR Pro S (Step-by-Step)
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1. Connect the CR Pro S
Plug the tool into your car’s OBD-II port (under the dashboard) and turn on the ignition.
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2. AutoVIN Identify
The tool automatically detects your vehicle’s details—no manual entry needed.
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3. Scan for Codes
Select “Full System Scan” or “Transmission System Scan” to retrieve P0718 and related codes (e.g., P0715 for TFT sensor circuit malfunction, P0700 for transmission control system fault).
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4. Check Live Data
Monitor TFT sensor voltage and temperature readings—fluctuating values or no consistent signal confirm an intermittent circuit issue.
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5. Test Components
Use bi-directional control to verify TCM communication with the TFT sensor—no response points to wiring/sensor faults; inconsistent response indicates intermittent connections.
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6. Fix the Root Cause
Replace the TFT sensor, repair wiring/connectors, top up/replace transmission fluid, or service the TCM (based on your findings).
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7. Clear the Code
Use the “Erase Codes” function to reset P0718 and warning lights.
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8. Re-Scan & Verify
Run a follow-up scan after driving to ensure the code doesn’t return—confirm the TFT sensor and transmission system are working properly.
FAQs About P0718 & the iCarsoft CR Pro S
Q: Can I drive with P0718?
A: You can drive short distances, but harsh shifting and transmission overheating risks make prompt diagnosis with the CR Pro S recommended. Avoid heavy loads or high speeds.
Q: Will the CR Pro S work with my car to diagnose P0718?
A: Yes! It supports over 60 global makes and all 1996+ OBD-II compliant vehicles with automatic transmissions.
Q: Do I need mechanical experience to use the CR Pro S for P0718?
A: No! Its 5-inch touchscreen, AutoVIN function, and clear instructions make it user-friendly for beginners. It highlights transmission components for easy reference.
Q: Can the CR Pro S distinguish between a faulty TFT sensor and wiring issues?
A: Absolutely. Live data shows signal consistency—erratic readings with intact wiring point to a faulty sensor; intermittent signals with wire movement indicate wiring problems.
Q: After fixing P0718, will the CR Pro S clear the code permanently?
A: Yes—once the root cause (e.g., faulty sensor, loose wiring) is addressed, the “Erase Codes” function clears P0718 permanently. If it returns, the issue wasn’t fully resolved.
Q: Is the CR Pro S better than a basic scanner for P0718?
A: Basic scanners only show P0718—they can’t monitor live TFT data or test TCM communication. The CR Pro S identifies why the signal is erratic, saving you from unnecessary part replacements.
Q: Does the CR Pro S support hybrid vehicles with P0718?
A: Yes! Hybrids with automatic transmissions rely on TFT sensors, and the CR Pro S includes specialized hybrid diagnostic functions to handle P0718.
Q: How often should I update the CR Pro S for P0718 diagnostics?
A: Update every 3–6 months via free Wi-Fi updates to ensure compatibility with new transmission systems and sensor technologies.
Final Thoughts: Don’t Let P0718 Damage Your Transmission
Fault code P0718 directly impacts your transmission’s health and performance by disrupting temperature-based control. With the iCarsoft CR Pro S, you can diagnose and fix it from your garage—no expensive dealership visits required. Its deep transmission system coverage, live data monitoring, and bi-directional control take the guesswork out of repairs, whether you’re a DIY enthusiast or professional mechanic.
Invest in the iCarsoft CR Pro S today to tackle P0718 and hundreds of other transmission-related codes—keep your vehicle shifting smoothly and reliably.
