Circuit Description
The automatic transmission fluid temperature (TFT) sensor is part of the automatic transmission fluid pressure (TFP) manual valve position switch. The TFT sensor is a resistor, or thermistor, which changes value based on temperature. 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 powertrain control module (PCM) supplies a 5-volt reference signal to the sensor on the TFT sensor signal circuit and measures the voltage drop in the circuit. When the transmission fluid is cold, the sensor resistance is high and the PCM detects high signal voltage. As the fluid temperature warms to a normal operating temperature, the resistance becomes less and the signal voltage decreases. The PCM uses this information to control shift quality and torque converter clutch apply.
When the PCM detects one of the following unusual conditions, then DTC P0711 sets.
| • | An unrealistically large change in transmission temperature |
| • | A transmission temperature which remains constant for a period of time in which a measurable amount of change is expected |
DTC P0711 is a type C DTC.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC P0711 Transmission Fluid Temperature (TFT) Sensor Performance
Conditions for Running the DTC
| • | No vehicle speed sensor (VSS) DTCs P0502 or P0503. |
| • | No Transmission Component Slipping DTC P0894. |
| • | No Engine Coolant DTCs P0117 or P0118. |
| • | The engine is running for 409 seconds. |
| • | The engine coolant temperature (ECT) is greater than 80°C (176°F) and the temperature has changed by 50°C (90°F) since startup. |
| • | The vehicle speed is greater than 20 km/h (12 mph) for 750 seconds cumulative during the current ignition cycle. |
| • | The TFT at startup is between -40 and +21°C (-40 and +70°F), or between +135 and +150°C (+275 and +302°F). |
| • | The TCC slip speed is greater than 80 RPM for 500 seconds cumulative during the current ignition cycle. |
Conditions for Setting the DTC
DTC P0711 sets if the following condition occurs:
The TFT does not change more than 2.25°C (4°F) for 80 seconds since startup.
Action Taken When the DTC Sets
| • | The PCM does not illuminate the malfunction indicator lamp (MIL). |
| • | The PCM calculates a default transmission fluid temperature based on engine coolant temperature, intake air temperature and engine run time. |
| • | The PCM freezes transmission adapt functions. |
| • | The PCM records the operating conditions when the Conditions for Setting the DTC are met. The PCM stores this information as Failure Records. |
Conditions for Clearing the DTC
| • | A scan tool can clear the DTC. |
| • | The PCM clears the DTC from PCM history if the vehicle completes 40 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 DTC passes. |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
This step tests for an intermittent short or open condition in the engine wiring harness. The test lamp is used as a resistor in the circuit.
-
This step determines if the PCM or the TFT sensor is causing a steady, unchanging TFT reading.
Step | Action | Values | Yes | No |
|---|---|---|---|---|
1 | Did you perform the Diagnostic System Check - Vehicle? | -- | Go to Step 2 | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information |
2 | Inspect for correct transmission fluid level. Refer to Transmission Fluid Check . Did you perform the fluid checking procedure? | -- | Go to Step 3 | Go to Transmission Fluid Check |
3 |
Important: Before clearing the DTC, use the scan tool in order to record the Failure Records. Using the Clear Info function erases the Failure Records from the PCM. The Trans. Fluid Temp. does not change more than 2.25°C (4°F) in 80 seconds since startup. Did this condition occur? | -- | Go to Step 4 | Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems |
4 | Did the scan tool display a condition in which the Trans. Fluid Temp. does not change by more than the specified value in 80 seconds since startup? | 2.25°C (4.0°F) | Go to Step 5 | Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems |
Does the scan tool display the same condition as in Step 4? | -- | Go to Step 7 | Go to Step 6 | |
Replace the TFT sensor. This sensor is part of the TFP manual valve position switch. Refer to Valve Body and Pressure Switch Replacement . Did you complete the replacement? | -- | Go to Step 8 | -- | |
7 | Replace the PCM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup and programming. Did you complete the replacement? | -- | Go to Step 8 | -- |
8 | Perform the following procedure in order to verify the repair:
The Trans. Fluid Temp. changes by more than 2.0°C (35.6°F) for 5 seconds since startup Has the test run and passed? | -- | Go to Step 9 | Go to Step 2 |
9 | 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 in Vehicle DTC Information | System OK |
