Circuit Description
The Automatic Transmission Fluid Temperature (TFT) sensor is a negative coefficient thermistor whose resistance value changes based on temperature. The Powertrain Control Module (PCM) provides a 5 volt reference to the sensor on circuit 1227. A low fluid temperature or open circuits 1227 or 452 result in high signal voltage. The TFT operating range is -40 to +151°C (-40 to +305°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 Setting the DTC
| • | The engine run time is greater than 5 minutes. |
| • | The vehicle speed is greater than 16 km/h (10 mph) for 5 minutes. |
| • | The engine coolant temperature is greater than -25°C (-13°F). |
| • | The PCM detects a reading of -40°C (-40°F) or less (5.04 volts or greater) for 6 seconds. |
Action Taken When the DTC Sets
| • | The PCM does not illuminate the Malfunction Indicator Lamp (MIL). |
| • | If any engine coolant temperature sensor codes set, the PCM substitutes a transmission fluid temperature default value of 132°C (269°F). |
| • | If the engine coolant temperature is greater than 115°C (239°F), the PCM substitutes a transmission fluid temperature default value of 132°C (269°F). This enables transmission Hot Mode. The transmission remains in Hot Mode until the engine coolant temperature drops below 110°C (230°F). |
| • | If the engine run time is less than 3 minutes, the PCM substitutes the intake air temperature for the transmission fluid temperature value at ignition ON. |
| • | If the engine coolant temperature is 45-115°C (113-239°F), the transmission fluid default temperature equals ECT - 10°C (50°F) when the intake air temperature is less than 27°C (81°F) at ignition ON. If the intake air temperature is greater than 27°C (81°F) at ignition ON, the transmission fluid default temperature equals ECT + 10°C (50°F). |
| • | If engine run time is greater than 3 minutes and the engine coolant temperature is less than 45°C (113°F), the PCM substitutes a transmission fluid temperature default value of 12°C (54°F). |
| • | DTC P0713 is stored in the PCM history. |
Conditions for Clearing the DTC
| • | A scan tool can clear the DTC from the PCM history. The PCM clears the DTC from the PCM history if the vehicle completes 40 warm-up cycles without a failure reported. |
| • | 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 20-way connector, and the TFT sensor 2-way connector for the following conditions: |
| - | A bent terminal |
| - | A backed out terminal |
| - | A damaged terminal |
| - | Poor terminal tension |
| - | A chafed wire |
| - | A broken wire inside the insulation |
| - | Moisture intrusion |
| • | When diagnosing for an intermittent open, massage the wiring harness while watching the test equipment for a change. |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
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If the display does not indicate a TFT sensor voltage greater than 4.98 volts, inspect the connectors and the terminal for intermittent conditions.
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Important: After 7 seconds, the Scan Tool will display a default temperature.
This step isolates the automatic transmission wiring harness by using a fused jumper from terminal M to the transmission case. Inspect the engine wiring harness circuit 1227 and circuit 452 for an open.
Step | Action | Value(s) | Yes | No | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
1 | Was the Powertrain On-Board Diagnostic (OBD) System Check performed? | -- | Go to Powertrain On Board Diagnostic (OBD) System Check in Engine Controls | |||||||
2 | Has the transmission fluid checking procedure been performed? | -- | Go to Transmission Fluid Check | |||||||
Important: Before clearing the DTC(s), use the Scan Tool in order to record the Failure Records for reference. Using the Clear Info function will erase the stored Failure Records from the PCM. Does the Scan Tool display a TFT sensor voltage equal to or greater than the specified value? | 4.98 V | Go to Diagnostic Aids | ||||||||
Does the Scan Tool display a TFT sensor voltage equal to or greater than the specified value? | 4.98 V | |||||||||
5 | Inspect circuit 1227 of the engine wiring harness for an open. Refer to General Electrical Diagnosis in Wiring Systems. Did you find and correct the condition? | -- | ||||||||
6 | Inspect circuit 452 of the engine wiring harness for an open. Refer to General Electrical Diagnosis in Wiring Systems. Did you find and correct the condition? | -- | ||||||||
7 |
Refer to General Electrical Diagnosis in Wiring Systems. Did you find the condition? | -- | ||||||||
8 | Replace the automatic transmission wiring harness. Refer to Transmission Overhaul in the 4T80-E Section of the Transmission Unit Repair Manual. Is the replacement complete? | -- | -- | |||||||
9 | Replace the TFT Sensor. Refer to Transmission Overhaul in the 4T80-E Section of the Transmission Unit Repair Manual. Is the replacement complete? | -- | -- | |||||||
10 | Replace the PCM. Refer to Powertrain Control Module Replacement/Programming in Engine Controls. Is the replacement complete? | -- | -- | |||||||
11 | In order to verify your repair, perform the following procedure:
Has the test run and passed? | -- | System OK |
