For 1990-2009 cars

### Circuit Description

The automatic transmission fluid temperature (TFT) sensor is part of the internal automatic transmission wiring harness assembly. The TFT sensor is a thermistor, or a resistor that changes value when the temperature changes. The sensor has a negative-temperature coefficient. This means that as the temperature increases, the resistance decreases, and as the temperature decreases, the resistance increases. The transmission control module (TCM) supplies a 5-volt reference signal to the sensor and measures the voltage drop in the circuit. When the transmission fluid is cold, the sensor resistance is high and the TCM detects high signal voltage. As the fluid temperature increases, the resistance of the sensor decreases, which lowers the signal voltage.

If the TCM detects an open in the TFT sensor or signal circuit, then DTC P0713 sets. DTC P0713 is a type A DTC.

### DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC P0713 Transmission Fluid Temperature (TFT) Sensor Circuit High Voltage

### Conditions for Running The DTC

• | No ECT DTCs.

• | Trans. Protection Mode is OFF.

• | ECT is greater than 50°C (122°F).

• | The engine run time is 15 minutes or greater.

• | The ignition voltage is 8-18 volts.

### Conditions for Setting The DTC

The TCM detects a transmission fluid temperature of -40°C (-40°F) or less for 12 seconds.

### Action Taken When the DTC Sets

• | The TCM requests the powertrain control module (PCM) to illuminate the malfunction indicator lamp (MIL).

• | DTC P1719 is disabled.

• | No lock-up slip neutral control or uphill/downhill control until transmission fluid temperature is greater than 40°C (104°F) for 5 seconds.

• | The TCM discontinues updating the transmission adaptive pressure (TAP) memory cells.

• | The TCM uses 30°C (86°F) as a default transmission fluid temperature.

• | The PCM records the operating conditions when the Conditions for Setting the DTC are met. The PCM stores this information as Freeze Frame and Failure Records.

• | The TCM records the operating conditions when the Conditions for Setting the DTC are met. The TCM stores this information as a Failure Record.

• | The TCM stores DTC P0713 in TCM history.

### Conditions for Clearing the DTC

• | The PCM turns off the MIL after the third consecutive drive trip in which the TCM does not send a MIL illumination request.

• | A scan tool can clear the MIL/DTC.

• | The TCM clears the DTC from TCM history if the vehicle completes 40 warm-up cycles without an emission-related diagnostic fault occurring.

• | The TCM cancels the DTC default actions when the ignition switch is OFF long enough in order to power down the TCM.

### Test Description

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

1. A short to voltage condition will open the TFT senor.

1. This step tests the internal transmission wiring harness assembly for a short to voltage.

Step | Action | Values | Yes | No
--- | --- | --- | --- | ---
1 | Did you perform the Diagnostic System Check - Vehicle? | -- | Go to Step 2 | Go to Diagnostic System Check - Vehicle
2 |

1. Install a scan tool.
2. Turn the ignition ON, with the engine OFF.

Important: Before clearing the DTC, use the scan tool in order to record the Freeze Frame and Failure Records. Using the Clear Eng./Trans. DTC Info function erases the Freeze Frame and Failure Records from the transmission control module (TCM).

3. Record the DTC Failure Records.
4. Clear the DTC.
5. Observe Trans. Fluid Temp. on the scan tool.

Does the scan tool display a Trans. Fluid Temp. less than or equal to the specified value?

-40°C (-40°F)

Go to Step 3

Go to Testing for Intermittent Conditions and Poor Connections

3 |

1. Turn the ignition OFF.
2. Disconnect the AT inline 14-way connector.
3. Using the DMM and J 35616 GM terminal test kit, measure the resistance between the transmission fluid temperature (TFT) signal circuit and the TFT sensor low reference circuit of the automatic transmission. Refer to Testing for Continuity .

Is the resistance greater than the specified value?

100 K ohms

Go to Step 4

Go to Step 5

4 | Test the TFT signal circuit and the TFT low reference circuit for a short to voltage between the transmission 14-way pass-through connector and the TCM. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 10 | Go to Step 8
5 | Test the TFT signal circuit and the TFT low reference circuit for continuity with any other circuit at the transmission 14-way pass-through connector. Refer to Testing for Continuity and Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 10 | Go to Step 6
6 | Test the TFT signal circuit and the TFT low reference circuit for an open or a short to voltage between the TCM connector and the transmission 14-way harness connector. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 10 | Go to Step 7
7 | Inspect the transmission 14-way connector and the TCM C2 connector for poor connections. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | -- | Go to Step 10 | Go to Step 9
8 | Replace the internal automatic transmission wiring harness assembly. The TFT sensor is a part of the harness assembly. Did you complete the replacement? | -- | Go to Step 10 | --
9 | Replace the TCM. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement? | -- | Go to Step 10 | --
10 | Perform the following procedure in order to verify the repair:

1. Select DTC.
2. Select Clear Info.
3. Drive the vehicle and ensure the following conditions are met:

• | The Trans. Fluid Temp. parameter is between -39°C and +149°C (-38°F and +300°F).

• | The Trans. Fluid Temp. parameter changes by more than 5°C (41°F) since start-up.

4. Select Specific DTC.
5. Enter DTC P0713.

Does the DTC reset?

--

Go to Step 2

Go to Step 11

11 | With the scan tool, observe the stored information, capture info and DTC info. Does the scan tool display any DTCs that you have not diagnosed? | -- | Go to Diagnostic Trouble Code (DTC) List - Vehicle | System OK