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 after the fixed resistor, as the signal voltage to the TFT circuit.
If the PCM detects an intermittent voltage, or no voltage change, indicating no temperature change from a cold startup, then DTC PO711 sets. DTC PO711 is a type D DTC.
Conditions for Setting the DTC
| • | No VSS DTCs P0502 or P0503. |
| • | System voltage is 10-16 volts. |
| • | No Transmission Component Slipping DTC P1870. |
| • | The TFT at start up is -40 to 21°C (-40 to 69°F) |
| • | The engine run time is 5 minutes or more. |
| • | The vehicle speed is 8 km/h (5 mph) or more for 7 minutes or more, cumulative this ignition cycle. |
| • | The TCC slip speed is 120 RPM or more for 7 minutes, cumulative this ignition cycle. |
| • | The ECT is 70°C (158°F) or more. |
| • | The ECT has changed 50°C (90°F) or more since start up. |
| • | The TFT voltage is 0.20-4.92 volts. |
All of the above must be true and one of the following fail cases must be true:
| • | Fail Case 1 |
| The change in TFT is 1.5°C (2.7°F) or less since start up for 7 minutes or more. |
| • | Fail Case 2 |
| The change in TFT is 20°C (36°F) or more within 0.2 seconds for 14 times or more within a 7 second period. |
Action Taken When the DTC Sets
| • | The PCM illuminates the Malfunction Indicator Lamp (MIL). |
| • | If the Engine Run Time is less than 3 minutes and: |
| - | The Intake Air Temperature (IAT) DTCs P0112, P0113, P1111 or P1112 is set, then the default Automatic Transmission Fluid Temperature (TFT) is set to 0°C (32°F). |
| - | No IAT DTC is set, then the default TFT is set to the IAT value which was saved at start up. |
| • | If the engine run time is greater than 3 minutes and: |
| - | The Engine Coolant Temperature (ECT) DTC(s) 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 12°C (54°F). |
| • | The ECT is greater than 115°C (239°F), then the default TFT is 131°C (268°F). |
| - | No ECT DTC is set, the ECT is 45-115°C (113-239°F) and: |
| • | The IAT DTC(s) P0112, P0113, P1111 or P1112 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 to 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 to equal the ECT value. |
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 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 |
| • | Test the TFT sensor at various temperature levels to evaluate the possibility of a skewed (mis-scaled) sensor. |
| • | Refer to Temperature vs Resistance (TFT) Table. |
| • | When diagnosing for an intermittent short or open condition, 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.
-
This step tests for proper A/T fluid level and condition.
-
This step verifies which condition has set DTC P0711.
-
The 12-volt test lamp is used as a fixed resistance.
-
This step ensures that the VCM monitors circuit 1227.
Step | Action | Value(s) | Yes | No | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
1 | Was the Powertrain On-Board Diagnostic (OBD) System Check performed? | -- | ||||||||
Perform the Transmission Fluid Checking Procedure. Did you perform the Transmission Fluid Checking Procedure? | -- | Go to Transmission Fluid Check | ||||||||
Important:: Before clearing the DTCs, use the scan tool in order to record the Freeze Frame and Failure Records for reference. The Clear Info function will erase the Failure Records from the PCM.
Did either of the fail conditions occur? | -- | Fault is not present. Refer to Diagnostic Aids | ||||||||
4 | Did the scan tool display unrealistic TFT voltage fluctuations? | -- | ||||||||
Does the scan tool display an unrealistic TFT voltage fluctuation? | -- | |||||||||
Is the scan tool TFT the same as recorded before separating the connector? | -- | |||||||||
7 | Replace the PCM. Refer to Powertrain Control Module Replacement/Programming . Is the replacement complete? | -- | -- | |||||||
8 | Replace the TFT Sensor. Refer to Fluid Temperature Sensor Replacement . Is the replacement complete? | -- | -- | |||||||
9 | In order to verify your repair, perform the following procedure:
Has the test run and passed? | -- | System OK |
