P0712

Circuit Description with 4T80-E Automatic Transaxle

Schematic:

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; 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 +151°C (-40 to +305°F). If the PCM detects a continuous short to ground in the TFT sensor circuit, then DTC P0712 sets. DTC P0712 is a type C DTC.

CONDITIONS FOR RUNNING THE DTC
^ The system voltage is 8-18 volts.
^ The engine run time is greater than 5 seconds.
^ The engine is not in fuel cut off.

CONDITIONS FOR SETTING THE DTC
The PCM detects a TFT of 149°C (300°F) or greater for 10 seconds.

ACTION TAKEN WHEN THE DTC SETS
^ The PCM does not illuminate the Malfunction Indicator Lamp (MIL).
^ The PCM calculates a default transmission fluid temperature based on engine coolant temperature, intake air temperature and engine run time.
^ The PCM records the operating conditions when the Conditions for Setting the DTC are met. The PCM stores this information as Failure Records.
^ The PCM stores DTC P0712 in PCM history.

CONDITIONS FOR CLEARING THE DTC
^ A scan tool can clear the DTC.
^ The PCM clears the DTC from PCM history if the vehicle completes 40 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/or the ignition switch is OFF long enough in order to power down the PCM.

DIAGNOSTIC AIDS
^ Inspect the connectors at the PCM, the TFT sensor, and all other circuit connecting points for an intermittent condition. Refer Testing for Intermittent and Poor Connections to in Diagrams.
^ Inspect the circuit wiring for an intermittent condition. Refer to Testing for Electrical Intermittents in Diagrams.

TEST DESCRIPTION

Steps 1 - 9:

Steps 10 - 11:

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 equal to or greater than 149°C (300°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.