P1718 — TFT Sensor In Range Failure Low Value

OBD2 code P1718 flags a problem with the sensor and actuator circuits (TFT sensor in range failure low value). The car is usually drivable while you plan the repair. Common culprits: control module driver fault, blown fuse feeding the circuit, poor ground connection.

For Ford vehicles

transmission fluid temperature sensor

powertrain (engine/transmission)

Is it safe to drive?

Short-term driving is OK In most cases the car remains drivable, possibly with reduced performance or a disabled auxiliary system. If symptoms include stalling, no-start or brake/steering warnings, treat it as urgent.

How to diagnose with an OBD scanner

Read the code and freeze frame Connect an OBD2 scanner, confirm P1718 is stored, and save the freeze frame data — it shows engine conditions when the fault was detected.
Check for companion codes and TSBs Related codes often reveal the real root cause. Also check manufacturer technical service bulletins (TSB) for your make and model — many P0xxx issues have factory fixes or software updates. Search by VIN on the manufacturer site or nhtsa.gov.
Inspect wiring and connectors Visually inspect the wiring harness and connectors related to the TFT sensor in range failure low value for damage, corrosion, chafing or poor contact.
Subsystem check Measure reference voltage, ground and signal continuity at the component connector.
Subsystem check Wiggle-test the harness while watching the signal in live data — dropouts reveal broken wires.
Verify the repair Clear the code, complete a full drive cycle including the conditions from the freeze frame, and confirm P1718 does not return.

Approximate repair cost

Repair cost depends on which component actually failed. Typical scenarios for P1718 (parts and labor, USD, independent shop rates): Replace the faulty sensor or actuator: $150–$500; Control module repair: $300–$1,000; Repair wiring or connectors: $80–$250. Overall, fixing P1718 usually costs between $80 and $1,000. An accurate diagnosis before buying parts saves money — the most expensive scenario is rarely the first one to check.

Common questions

What does OBD2 code P1718 mean?

What are the symptoms of P1718?

Drivers most often notice: Check Engine Light on, possible limp mode depending on the affected component, the affected system operates intermittently or not at all, increased fuel consumption in some cases.

Is it safe to drive with P1718?

In most cases the car remains drivable, possibly with reduced performance or a disabled auxiliary system. If symptoms include stalling, no-start or brake/steering warnings, treat it as urgent.

How do I diagnose P1718 myself?

Start with a scan: confirm P1718, save the freeze frame and note any companion codes. Then inspect the wiring and connectors related to the sensor and actuator circuits, and verify the suspect component against live data before buying parts.

Will P1718 clear itself?

Sometimes P1718 clears after a few drive cycles if the fault was intermittent — for example a loose connector or a tank of bad fuel. The underlying cause usually remains, so the code tends to return. Clear it once; if it comes back, diagnose rather than erase it repeatedly.

The Transmission Fluid Temperature (TFT) sensor tracks how hot your transmission fluid runs and feeds that data back to the vehicle's control modules. This information influences shift timing, torque converter lockup, and line pressure across the transmission system. When the signal from this sensor drops below what the engine computer expects to see under current operating conditions, it logs code P1718. In plain terms, the sensor is reporting a temperature value that reads too low — often stuck near its minimum reading even when conditions don't support that temperature.

The powertrain control module watches the TFT circuit constantly while you drive. It has defined acceptable ranges for what the sensor should output at various engine loads, speeds, and ambient temperatures. When the voltage signal stays below the lower threshold for longer than the programmed number of drive cycles, the module decides this isn't a one-time glitch and stores P1718. The check engine light comes on, and the system saves a freeze frame snapshot capturing RPM, load, vehicle speed, and fluid temperature at the exact moment the fault was first detected. That snapshot is your most valuable starting point for diagnosis, because it tells you exactly what conditions triggered the code.

P1718 specifically means the transmission fluid temperature sensor circuit is returning a voltage that falls below the expected minimum for the current driving scenario. Think of it like a thermometer stuck at its coldest mark — the system knows the engine and transmission are running, but the temperature reading doesn't match reality. Depending on how the manufacturer programmed the transmission logic, this can have minor effects or more serious consequences. The transmission computer may switch to a default strategy, change shift patterns, or limit power to protect internal components from conditions it can't accurately measure.

Common symptoms of P1718

The check engine light illuminates and stays on
The transmission may enter limp mode, restricting performance and preventing normal shifting
The affected system operates inconsistently or stops working entirely
Fuel consumption rises if the transmission shifts inefficiently due to incorrect fluid temperature data
In some vehicles, shift quality degrades noticeably — harsh engagements or failure to shift into higher gears

What causes P1718?

A corroded, loose, or physically damaged connector at the TFT sensor or its control module
Wiring with an open circuit or short to ground, often from chafing against hot or moving components
A blown fuse feeding the sensor circuit
The TFT sensor or its related actuator has failed internally
A poor or corroded ground connection at the transmission case
The control module's driver circuit for the sensor has malfunctioned — less common but possible

How to diagnose P1718

Plug in an OBD2 scanner and confirm P1718 is stored in the transmission or engine controller. Record the freeze frame data — this shows engine RPM, load, vehicle speed, and fluid temperature when the fault first occurred.
Check for any other stored codes. Related electrical faults often point to the root cause, such as a short or open circuit that needs addressing first. Review manufacturer TSBs for your specific make and model, as factory updates or known fixes may apply.
Inspect the wiring harness and connectors tied to the TFT circuit. Look for damaged insulation, broken strands, corrosion buildup, and loose pins that prevent solid contact.
At the component connector, verify reference voltage, ground integrity, and signal continuity with a multimeter. Compare your readings against factory specifications.
Perform a wiggle test on the harness while monitoring live data — any dropouts or signal interruptions expose broken wires inside the insulation.
Clear the code, then drive the vehicle through conditions matching the freeze frame data. Watch to confirm P1718 does not return.

Repair options with costs

Depending on what the diagnosis reveals, here are the typical repair approaches and what they typically cost at an independent shop (parts and labor, USD):

Replace a faulty TFT sensor or related actuator: $150–$500
Repair or replace damaged wiring or connectors: $80–$250
Control module diagnosis and repair or replacement: $300–$1,000

How much does it cost to fix P1718?

The total bill hinges on which part actually failed. Repairing a poor connection or wiring issue runs $80–$250 in most cases and resolves the problem without touching expensive components. Sensor or actuator replacement typically falls between $150 and $500 depending on the part cost and labor time for your specific vehicle. Control module work sits at the high end — $300–$1,000 — and only becomes necessary if diagnostics rule out the wiring and sensor. Overall, fixing P1718 generally costs between $80 and $1,000. An accurate diagnosis before purchasing parts always saves money, because the most expensive scenario is rarely the first one to blame.

Can you drive with P1718?

In most cases, yes — the vehicle remains drivable when P1718 is stored. You may notice the check engine light on, reduced transmission performance in limp mode, intermittent operation of the affected system, or worse fuel economy if shift patterns are affected. However, if the vehicle stalls, fails to start, or displays warnings related to braking or steering, treat it as urgent and have it assessed immediately.