Transmission

P0712 — Transmission Fluid Temperature Sensor Circuit Low

Severity: medium Drive with care, to a shop

What P0712 means

The transmission control module (or PCM) monitors the voltage from the transmission fluid temperature (TFT) sensor. The sensor's resistance changes as the fluid warms, and the module uses it to adjust line pressure and shift timing. P0712 sets when the circuit voltage drops too low, which the module reads as an impossibly hot fluid. The usual causes are a short to ground in the signal wire or a failed sensor.

Symptoms

  • Check engine or transmission warning light on
  • Harsh shifts, especially when cold
  • Delayed or banging shifts
  • Torque converter clutch not locking
  • Worse fuel economy
  • Transmission stuck in fail-safe mode

Possible causes

  1. Failed transmission fluid temperature sensor
  2. Signal wire shorted to ground in the harness
  3. Damaged or corroded connector at the transmission
  4. Wiring chafed against the body or pan
  5. Fluid or moisture inside the connector
  6. Faulty TCM or PCM (uncommon)

How to diagnose

  1. Scan for codes and view live transmission fluid temperature data
  2. Compare the reading with actual temperature on a cold engine; it should be near ambient
  3. Inspect the harness and transmission connector for damage, oil, and corrosion
  4. Unplug the sensor: if the reading jumps or the code changes to P0713, the wiring to the sensor is likely fine
  5. Measure the sensor resistance and compare it with specs for your vehicle
  6. Check the signal wire for a short to ground with the connector unplugged
  7. Check fluid level and condition
  8. If the wiring and sensor are good, test the control module

Common fixes

  • Replace the transmission fluid temperature sensor
  • Repair or replace the damaged wiring
  • Clean or replace the connector
  • Top off or replace the transmission fluid if needed
  • Repair or replace the control module (rare)

Questions and answers

What does P0712 mean?

The control module sees too low a voltage from the transmission fluid temperature sensor. It's usually a short to ground or a bad sensor.

Can I drive with P0712?

For a short time, yes, but the transmission may run in fail-safe mode without temperature monitoring. Fix it soon to avoid overheating the transmission.

How do I fix P0712?

Start by inspecting the connector and wiring at the transmission, then test the sensor. Replacing the sensor or repairing a shorted wire fixes most cases.

This is general information about the code. The meaning can differ between makes and models: a scan tool and the repair manual for your car will show the exact cause.