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 or open circuits 1227 or 452/808 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 Setting the DTC
| • | The system voltage is 9-16 volts. |
| • | The ignition is ON. |
| • | The PCM detects a TFT sensor voltage of greater than 4.92 volts for 7 minutes continuous. |
Action Taken When the DTC Sets
| • | The PCM does not illuminate the Malfunction Indicator Lamp (MIL). |
| • | The PCM disables shift adapts. |
| • | The default TFT will be determined through the following calculations: |
| - | If the engine run time is less than 3 minutes and: |
| • | Intake Air Temperature (IAT) DTC P0112, P0113, P1111 or P1112 is set, then the default Automatic Transmission Fluid Temperature (TFT) is 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 an Engine Coolant Temperature (ECT) DTC P0117, P0118, P1114 or P1115 is set, then the default TFT is 131°C (268°F). |
| - | If the engine run time is greater than 3 minutes, no ECT DTC is set and: |
| • | The ECT is 45°C (113°F) or less, then the default TFT is 12°C (54°F). |
| • | The ECT is 115°C (239°F) or greater, then the default TFT is 131°C (268°F). |
| • | The ECT is between 45 and 115°C (113 and 239°F) and: |
| - | The IAT DTC P0112, P0113, P1111 or P1112 is set, then the default TFT is set to equal the ECT. |
| - | The IAT at start up is 0°C (32°F) or less, then the default TFT is set to ECT minus 10°C (18°F). |
| - | The IAT at start up is 28°C (82°F) or greater, then the default TFT is set to ECT plus 10°C (18°F). |
| - | The IAT at start up is between 0 and 28°C (32 and 82°F), then the default TFT is set to equal ECT. |
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 for poor electrical connections at the PCM, the transmission 20-way connector and all other circuit connecting points 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 |
| - | Corrosion |
| • | When diagnosing for an intermittent 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.
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If the display does not indicate an Automatic Transmission Fluid Temperature Sensor voltage greater than 4.920 volts, inspect the connectors and the terminal for intermittent conditions.
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Important: After 10 seconds, the Scan Tool will display a default temperature.
This step inspects only the engine harness and the PCM 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 transmission fluid temperature voltage greater than the specified value? | 4.920 volts | Go to Diagnostic Aids | ||
Does the Scan Tool display a transmission fluid temperature voltage greater than the specified value? | 4.92 volts | |||
5 | Inspect circuit 1227 (YEL) 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 808 (BLK) 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 Fluid Temperature Sensor. Refer to Fluid Temperature Sensor Replacement . Is the replacement complete? | -- | -- | |
9 | Replace the Automatic Transmission Wiring Harness Assembly. Refer to Solenoids and Wiring Harness Replacement . 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, using the Scan Tool , perform the following procedure:
Has the test run and passed? | -- | System OK |
