Transmission Fluid Temperature Sensor Stuck High
The P1718 code indicates that the transmission control module (TCM) has detected the transmission fluid temperature (TFT) sensor reading is stuck above 250°F (121°C). This is an abnormally high temperature that can cause transmission damage. The sensor may be faulty, shorted, or there could be a wiring issue. Actual transmission overheating due to low fluid, a failing torque converter, or a clogged cooler can also trigger this code.
01. Most Common Causes
- Faulty transmission fluid temperature sensor
- Short or open in TFT sensor wiring or connector
- Low or contaminated transmission fluid
- Transmission overheating due to mechanical issues (e.g., torque converter, cooler blockage)
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Transmission may shift harshly or slip
- Transmission may enter limp mode or fail to shift
- Possible overheating warning or fluid smell
03. Step-by-Step Diagnosis
Step 1: Scan for codes and record freeze frame data.
Step 2: Inspect transmission fluid level and condition; top up or replace if necessary.
Step 3: Check TFT sensor wiring and connector for damage, corrosion, or loose pins.
Step 4: Test TFT sensor resistance and compare to manufacturer specifications; replace if out of range.
Step 5: If sensor and wiring are good, check for transmission overheating causes (cooler flow, torque converter slip).
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
No, driving with a transmission fluid temperature stuck above 250°F can cause severe internal damage. Have the vehicle towed to a shop.
How much does it cost to fix?▼
Diagnosis typically costs $50-$150. Replacing the TFT sensor is usually $100-$300 including parts and labor. If transmission overheating is due to other issues, costs can be higher.