P0713

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 low fluid temperature, an open TFT sensor or open circuits 1227 or 808/452 results in high signal voltage.the TFT operating range is -40 to +151°C (-40 to +304°F);

If the PCM detects a continuous open or a short to power on the TFT sensor circuit, then DTC P0713 sets. DTC P0713 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 greater than 4.92 volts for 6 minutes and 40 seconds continuous.

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 P0713 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 intermiffent open, 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. Refer to the Temperature vs Resistance table.

Test Description

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

3. If the display does not indicate a TFT sensor voltage greater than 4.92 volts, inspect the connector and the terminals for intermittent conditions.

Important: After 10 seconds, the scan tool will display a default temperature.

4. This step tests the integrity of the engine harness and the PCM by using a fused jumper wire from terminal L to terminal M. Voltage should be less than 0.2 volts.

10. Because of the harsh conditions inside the transmission, repairing the automatic transmission (A/T) wiring harness assembly is not acceptable. It must be replaced if it is damaged in any way.