P0712

DIAGNOSTIC TROUBLE CODE (DTC) P0712 TRANSMISSION FLUID TEMPERATURE (TFT) SENSOR CIRCUIT LOW INPUT





Circuit Description
The Automatic Transmission Fluid Temperature (TFT) sensor assembly is a thermistor and is part of the Automatic Transmission Fluid Pressure Manual Valve Position Switch (TFP Val. Position Sw.). The Powertrain Control Module (PCM) supplies a 5 volt reference signal to the sensor on circuit 506. When transmission fluid is cold, the sensor resistance is high and the PCM will sense a high signal voltage. As the transmission fluid warms, the sensor resistance lowers and the PCM senses lower voltage. The PCM uses the TFT readings to control Torque Converter Clutch (TCC) apply and release, fine pressure adjustments, and temperature compensated shifts.
When the PCM detects a continuous short to ground in the TFT signal circuit or the TFT sensor, then Diagnostic Trouble Code (DTC) P0712 sets.

Conditions For Setting The DTC
- Ignition is ON.
- TFT voltage is less then 0.33 volts for 10 seconds.

Action Taken When The DTC Sets
- PCM does not illuminate the Malfunction Indicator Lamp (MIL).
- Freeze shift adapts from being updated.
- Transmission default temperature will be calculated based on engine coolant temperature, manifold air temperature, and engine run time.
- DTC P0712 will be stored in PCM memory.

Conditions For Clearing The DTC
- When TFT voltage is greater than 0.33 volts for 3 seconds for three consecutive ignition cycles.
- History DTCs can be cleared by using a Scan Tool.

Diagnostic Aids
- Inspect the wiring for poor electrical connections at the PCM and at the transmission 20-way connector. Look for possible bent, backed out, deformed or damaged terminals. Check for weak terminal tension as well. Also check for chafed wires that could short to bare metal or other wiring. Inspect for broken wire inside the insulation.
- If diagnosing for a possible intermittent short or open condition, move or massage the wiring harness while observing test equipment for a change.
- DTC P0712 could set if the vehicle or transmission has been exposed to temperature above 150°C (300°F).

Test Description
The numbers below refer to the step numbers on the diagnostic chart.
3. This test checks the PCM's ability to detect an open circuit.
4. This test checks the TFT Sensor for correct resistance.








DTC P0712 - Transmission Fluid Temperature (TFT) Sensor Circuit Low Input