Powertrain, generic · Transmission

P0712 Transmission Fluid Temperature Sensor A Circuit Low

Check engine lightOn
EmissionsNot relevant
Drive cycleRequired
Limp modePossible

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.

Likely causes

Signal wire shorted to ground (internal harness, chafing)
Sensor shorted internally
Transmission actually severely overheated
Control module faulty

Symptoms

  • 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

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€80–600
Time1–4 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

transmission fluid temperature sensortransmission internal harnesstransmission control module

Related codes

P0710P0711P0713P0714P0218

References: gsi.ext.gm.com, gsi.ext.gm.com, gsi.ext.gm.com, saabwisonline.com.