Low or degraded transmission fluid level causing overheating; Faulty transmission fluid temperature sensor or damaged sensor wiring; Restricted transmission cooler or coolant flow to the cooler; Sticking or failed transmission thermostat (on models equipped); Heavy towing or aggressive driving under high ambient temperatures; Internal transmission wear generating excessive heat; Corroded or loose electrical connector at the transmission

DTC codes / Ford codes / P1718

P1718 · FordTFT Sensor In Range Failure High

Q: What does code P1718 mean?

TFT Sensor In Range Failure High. P1718 on Ford vehicles means the transmission control module has detected that the transmission fluid temperature sensor signal is higher than the normal operating range for the current conditions. The computer compares the sensor voltage against expected values and flags this code when the calculated temperature exceeds a calibrated threshold, indicating an over-temperature condition or a sensor circuit fault.

P1718 on Ford vehicles means the transmission control module has detected that the transmission fluid temperature sensor signal is higher than the normal operating range for the current conditions. The computer compares the sensor voltage against expected values and flags this code when the calculated temperature exceeds a calibrated threshold, indicating an over-temperature condition or a sensor circuit fault.

SystemPowertrain

Code typeFord specific

SeverityMedium

Fix difficultyIntermediate

AreaTransmission

Symptoms you may notice

Transmission may enter limp mode or fail-safe mode with harsh or delayed shifts
Temperature warning light or message displayed in the instrument cluster
Poor fuel economy and sluggish acceleration due to elevated fluid temperature
Transmission may slip or shudder, especially when hot
Often no symptoms besides the warning light, particularly if the fault is intermittent

Common causes, most likely first

Low or degraded transmission fluid level causing overheating
Faulty transmission fluid temperature sensor or damaged sensor wiring
Restricted transmission cooler or coolant flow to the cooler
Sticking or failed transmission thermostat (on models equipped)
Heavy towing or aggressive driving under high ambient temperatures
Internal transmission wear generating excessive heat
Corroded or loose electrical connector at the transmission

How to diagnose and fix it

Check transmission fluid level and condition; top off or replace fluid if burnt or low
Inspect the transmission fluid temperature sensor connector and wiring for damage or corrosion
Use a scan tool to read live transmission fluid temperature data and compare with actual fluid temperature after a cold soak
Test the sensor resistance with a multimeter and compare to Ford specifications for the current temperature
Inspect the transmission cooler and lines for restrictions or blockages; flush if necessary
Verify thermostat operation if equipped and replace if stuck closed
If the sensor and circuit test good, perform a transmission diagnostic procedure to check for internal faults causing overheating

Don't overlook the cooler and fluid condition

A restricted transmission cooler is a common cause of P1718 that many technicians miss because they focus only on the sensor circuit.
The code can set intermittently from a poor electrical connection at the transmission, so always wiggle-test the harness while watching live temperature data.
On some Ford models, the transmission fluid temperature sensor is part of the solenoid body assembly and cannot be replaced separately, requiring a more involved repair.
Heavy towing or mountain driving in high ambient temperatures can temporarily trigger P1718 without any defective parts, so check driving conditions before condemning components.
A failing transmission thermostat that stays closed will cause rapid overheating and set this code even when the sensor and wiring are perfect.

Can I keep driving with P1718?

You can drive the vehicle short distances at moderate speeds to a repair shop, but avoid towing, heavy loads, or sustained highway driving until the fault is diagnosed. Continuing to drive with an over-temperature condition can cause internal transmission damage and lead to costly repairs.

Tools that help

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Guidance is general and written for Ford vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.