P0713

Circuit Description

The transmission fluid temperature (TFT) sensor is a negative coefficient thermistor. When the transmission fluid is cold, the sensor resistance is high. As the transmission fluid warms, the sensor resistance decreases. The TFT range is -40 to +150°C (-40 to +302°F).

The PCM provides a 5 volt reference through a fixed resistor to the TFT circuit and monitors the voltage drop across the TFT sensor and harness.

When the PCM detects a continuous voltage input greater than 4.92 volts, indicating an open or short to power in the TFT Sensor circuit, then DTC P0713 sets. DTC P0713 is a type D DTC.

Conditions for Running the DTC

^ System voltage is 10-18 volts.
^ The ignition is ON.

Conditions for Setting the DTC

The PCM detects a transmission fluid temperature of -35°C (-31°F) or less (4.92 volts or more) for 7 minutes.

Action Taken When the DTC Sets

^ The PCM does not illuminate the malfunction indicator lamp (MIL).
^ If the engine run time is less than 3 minutes and:
- Any intake air temperature (IAT) DTC (P0112, P0113, P1111 or P1112) is set, then the default transmission fluid temperature is set to 0°C (32°F).
- No IAT DTC is set, then the default TFT is set to the IAT saved at start up.
^ If the engine run time is greater than 3 minutes and:
- Any engine coolant temperature (ECT) DTC (P0117, P0118, P1114 or P1115) is set, then the default TFT is set to 131°C (268°F).
- No ECT DTC is set, and:
^ The ECT is less than 45°C (113°F), then the default TFT is set to 12°C (54°F).
^ The ECT is greater than 115°C (239°F), then the default TFT is set to 131°C (268°F).
- No ECT DTC is set, the ECT is 45-115°C (113-239°F) and:
^ IAT DTC P0112 or P0113 is set, then the default TFT is set to equal the ECT.
^ The IAT at start up is less than 0°C (32°F), then the default TFT is set 10 the ECT value minus 10°C (18°F).
^ The IAT at start up is greater than 28°C (82°F), then the default TFT is set to the ECT value plus 10°C (18°F).
^ The IAT at start up is 0-28°C (32-82°F), then the default TFT is set equal to the ECT value.

Conditions for Clearing the DTC

^ A scan tool clears the DTC from PCM history.
^ The PCM clears the DTC from the 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 is OFF long enough in order to power down the PCM.

Diagnostic Aids

^ Inspect the wiring at the PCM, the transmission 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 or open, massage the wiring harness while watching the test equipment for a change.
^ Test the TFT Sensor at various temperature levels to check for a skewed or mis-scaled sensor.

Test Description

The numbers below refer to the step numbers on the diagnostic table.

3. A scan tool Trans. Fluid Temp. of -36°C (-33°F) or less indicates this DTC is current.
4. This step isolates the fault between the transmission harness or the engine harness.