Transmission Fluid Temperature Sensor Too High (Ford)
What does P1718 mean?
The P1718 code means the vehicle's onboard diagnostic system has detected: Transmission Fluid Temperature Sensor Too High (Ford). This is a critical severity code.
Common Symptoms
- Check Engine Light on
- Transmission overheating warning
- Burnt smell from transmission
- Harsh or erratic shifting
- Transmission slipping under load
Probable Causes (Ranked by Likelihood)
- Actual transmission overheating Very High
- Failed torque converter not locking up High
- Clogged transmission cooler Moderate
- Faulty TFT sensor reading falsely high Low
Step-by-Step Diagnostic Procedure
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Immediately stop the vehicle and let the transmission cool if the fluid smells burnt.
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Check transmission fluid level and condition. Low fluid or burnt fluid indicates a serious problem.
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Verify actual fluid temperature with an infrared thermometer on the pan. Normal is under 200F.
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Inspect the transmission cooler lines and cooler for blockage or restricted flow.
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If the fluid is not actually hot, test the TFT sensor resistance at known temperatures.
Frequently Asked Questions
What temperature is too hot for transmission fluid?
Transmission fluid should stay below 200F during normal operation. Above 240F, fluid begins to break down rapidly. Above 280F, damage occurs within minutes.
Can I add a transmission cooler?
Yes. An auxiliary transmission cooler is an excellent upgrade, especially for towing. It significantly reduces operating temperature and extends fluid life.
Will overheating ruin my transmission?
Repeated overheating breaks down fluid, burns clutch material, and damages seals. If caught early and the fluid is changed, damage may be limited. Severely burnt fluid usually means internal damage.