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 P0711 sets. DTC P0711 is a type D DTC.
Conditions for Running the DTC
| • | No VSS DTC P0502 or P0503. |
| • | System voltage is 10-18 volts. |
| • | No Transmission Component Slipping DTC P1870. |
| • | The TFT at start up is -40 to 21°C (-40 to 69°F) |
| • | The TFT voltage is 0.20-4.92 volts. |
| • | 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. |
Conditions for Setting the DTC
DTC P0711 sets if one of the following is 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 does not illuminate the malfunction indicator lamp (MIL). |
| • | If the engine run time is less than 3 minutes and: |
| - | Any intake air temperature (IAT) DTC (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: |
| - | Any engine coolant temperature (ECT) DTC (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: |
| • | Any 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 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 clears the DTC from PCM history. |
| • | The PCM clears the DTC from the 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 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 backed out terminal |
| - | A damaged terminal |
| - | Reduced 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 or mis-scaled sensor. Refer to Temperature vs Resistance 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 AT 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 PCM 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 Failure Records. Using the Clear Info function erases the Failure Records from the PCM. Important:: At approximately 50°C (122°F), TFT voltage will switch between approximately 1.1 volts and 3.5 volts due to a shunt resistor in the PCM. Refer to Temperature vs Resistance .
Did either of the fail conditions occur? | -- | Go 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 from step 3? | -- | |||||||||
7 | Replace the PCM. Refer to Powertrain Control Module Replacement/Programming in Engine Controls. Is the replacement complete? | -- | -- | |||||||
8 | Replace the TFT sensor. Refer to Fluid Temperature Sensor Replacement . Is the replacement complete? | -- | -- | |||||||
9 | Perform the following in order to verify the repair:
Has the test run and passed? | -- | System OK |
