Obdaryn

P0712Transmission Fluid Temperature Sensor A Circuit Low

  • Generic OBD-II code · Powertrain
  • Turns on the check-engine light
  • Can trigger limp mode
  • Needs a drive cycle to confirm a fix
How the car detects it
The transmission fluid temperature sensor is an NTC thermistor whose resistance falls as the fluid warms; the module feeds it with 5 V through a resistor. A low signal therefore means very hot or a short to ground, a high signal very cold or an open circuit. P0712 means the signal is too low – the sensor reads extremely hot, or the signal wire is shorted to ground. GM's 2025 transmission modules flag below 13.5 Ω for 5 of 6 s after two trips; the 2018 LT4 engine module below 17.88 Ω (over 150 °C) without MIL; the 2007 Allison 1000 150 °C or more for 2.5 s; Saab's AF40 over 200 °C; Ford below 0.05 V for 5–12 s without MIL. The module substitutes a value (coolant temperature, 80 °C or a hot mode) and may shift with hot-fluid strategy. Real overheating with a good sensor is P0218.
What you may notice
  • Transmission in hot mode (early converter clutch, changed shift points)
  • Harsh shifts
  • Extremely high fluid temperature shown
  • Check engine or transmission lamp depending on manufacturer
Likely causes
  • LikelySignal wire shorted to ground (internal harness, chafing)
  • PossibleSensor shorted internally
  • RareTransmission actually severely overheated
  • RareControl module faulty
Repair
Medium · Usually a job for a workshop.Typical cost: €80 – €600

Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.