4T80-E Automatic Transaxle
DTC P0712
Circuit Description
The automatic transmission fluid temperature (TFT) sensor is a negative coefficient thermistor whose resistance value changes based on temperature. The transmission control module (TCM) provides a 5 volt reference to the sensor. A high fluid temperature or a short to ground on the signal circuit results in low signal voltage. The TFT operating range is -40 to +150°C (-40 to +302°F).
If the TCM detects a continuous short to ground in the TFT sensor circuit, then DTC P0712 sets. DTC P0712 is a type C DTC.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC P0712 Transmission Fluid Temperature (TFT) Sensor Circuit Low Voltage
Conditions for Running the DTC
* No Trans. Temp. DTCs P0218, P0711 or P0713.
* The engine run time is greater than 5 seconds.
Conditions for Setting the DTC
The TCM detects a TFT of greater than 150°C (302°F) for 12 seconds.
Action Taken When the DTC Sets
* The TCM does not request the engine control module (ECM) to illuminate the malfunction indicator lamp (MIL).
* The TCM freezes transmission adaptive functions.
* The TCM calculates a default transmission fluid temperature based on engine coolant temperature, intake air temperature and engine run time.
* The TCM records the operating conditions when the Conditions for Setting the DTC are met. The TCM stores this information as Failure Records.
* The TCM stores DTC P0712 in TCM history.
Conditions for Clearing the DTC
* The TCM clears the DIC message when the condition no longer exists.
* A scan tool can clear the DIC/DTC.
* The TCM clears the DTC from TCM history if the vehicle completes 40 warm-up cycles without a non-emission related diagnostic fault occurring.
* The TCM cancels the DTC default actions when the fault no longer exists and the DTC passes.
Test Description
The numbers below refer to the step numbers on the diagnostic table.
2. This step verifies DTC P0712 by indicating a short to ground. If the scan tool does not display a transmission fluid temperature greater than 150°C (302°F), then the DTC is intermittent.
3. This step isolates the transmission. If the scan tool displays a transmission fluid temperature less than -38°C (-36°F), then the engine wiring harness is good.
