P0712

Circuit Description
The automatic transmission fluid temperature (TFT) sensor is a negative coefficient thermistor whose resistance value changes based on temperature. The PCM provides a 5 volt reference to the sensor on circuit 1227. A high fluid temperature or a short to ground on circuit 1227 results in low signal voltage. The TFT sensor operating range is -40 to +151°C (-40 to +304°F).
If the PCM detects a continuous short to ground in TFT sensor circuit 1227, then DTC P0712 sets. DTC P0712 is a type D DTC.

Conditions for Running the DTC
The system voltage is 9-18 volts.

Conditions for Setting the DTC
The PCM detects a TFT sensor voltage of 0.2 volts or less for 10 seconds.

Action Taken When the DTC Sets
^ The PCM does not turn on the malfunction indicator lamp (MIL).
^ The PCM freezes shift adapts.
^ The PCM calculates a default TFT from the ECT sensor and the IAT sensor.
^ The PCM stores DTC P0712 in PCM history.

Conditions for Clearing the DTC
^ A scan tool clears the DTC from PCM history. The PCM clears the DTC from PCM history if the vehicle completes 40 consecutive warm-up cycles without a non-emission-related diagnostic fault occurring.
^ The PCM cancels the DTC default actions when the fault no longer exists and the ignition switch is OFF long enough in order to power down the PCM.

Diagnostic Aids
^ Inspect the wiring at the PCM, the transmission 20-way connector and all Other circuit connecting points for the following conditions:
- A backed out terminal
- A damaged terminal
- Reduced terminal tension
- A chafed wire
- A broken wire inside the insulation
- Moisture intrusion
- Corrosion
^ When diagnosing for an intermittent short to ground or short to power, massage the wiring harness while watching the test equipment for a change.
^ Test the TFT sensor at various temperature levels to evaluate the possibility of a skewed (mis-scaled) sensor.

Test Description
The numbers below refer to the step numbers on the diagnostic table.
3. This step tests the PCMs ability to detect an open circuit.
5. This step tests the TFT sensor for correct resistance.