P0710: OBD-II code P0710 flags a fault in the transmission fluid temperature (TFT) sensor circuit — the TCM can't measure fluid temperature for shift adaptation.

Symptoms

• Check engine light is on; the transmission may shift harshly or in the wrong gears because the TCM defaults to safe values.
• TCC lock-up may be delayed or disabled to protect against unknown fluid temperature.
• The vehicle may lack normal cold or hot shift adaptation, feeling unresponsive.

Common causes

• A failed TFT sensor with an open or shorted internal thermistor.
• Damaged wiring or a corroded connector at the transmission solenoid harness.
• Contaminated transmission fluid coating the sensor and biasing its readings.

What to do?

Read live TFT and compare to actual fluid temperature. Replace the sensor (often integrated with the solenoid pack on modern transmissions) if it reads out of spec. Change the transmission fluid if it is contaminated.