Circuit Description
The Automatic Transmission Fluid Temperature (TFT) Sensor is part of the Automatic Transmission Fluid Pressure Manual Valve Position Switch (TFP Val. Position Sw.). 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 Vehicle Control Module (VCM) supplies a 5 volt reference signal to the sensor on circuit 1227 and measures the voltage drop in the circuit. When the transmission fluid is cold, the sensor resistance is high and the VCM detects high signal voltage. As the fluid temperature warms to a normal operating temperature, the resistance becomes less and the signal voltage decreases. The VCM uses this information to control shift quality and torque converter clutch apply.
When the VCM 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 D DTC.
Conditions for Setting the DTC
| • | No VSS Assy. DTCs P0502 or P0503. |
| • | No Transmission Component Slipping DTC P1870. |
| • | The system voltage is 10-16 volts. |
| • | The engine is running for 409 seconds. |
| • | The vehicle speed is greater than 8 km/h (5 mph) for 409 seconds cumulative this ignition cycle. |
| • | The TCC slip speed is greater than 120 RPM for 409 seconds cumulative this ignition cycle. |
| • | The transmission fluid temperature at startup is between -40 and +21°C (-40 and +70°F). |
| • | The TFT is between -38 and +151°C (-36 and +304°F). |
| • | The engine coolant temperature is greater than 70°C (158°F) and the temperature has changed by 50°C (90°F) since startup. |
| • | All of the above conditions are met and either of the following fail conditions occurs: |
| - | The transmission fluid temperature does not change more than 1.50°C (2.7°F) for 409 seconds since startup. |
| - | The transmission fluid temperature changes more than 20°C (36°F) in 200 milliseconds 14 times within 7 seconds. |
Action Taken When the DTC Sets
| • | The VCM does not illuminate the Malfunction Indicator Lamp (MIL). |
| Important: The scan tool does not indicate the default TFT. |
| • | The VCM determines a default Transmission Fluid Temperature (TFT) using the following matrix: |
| Important: The actions listed below are in order of highest to lowest priority. |
| 1. | If any Engine Coolant Temperature (ECT) DTCs P0117 or P0118 are set, then the default TFT is equal to 135°C (275°F). |
| 2. | If the ECT is 125°C (257°F) or more, then the default TFT is equal to 135°C (275°F). |
| 3. | If the Engine Run Time is less than 300 seconds and: |
| • | No Intake Air Temperature (IAT) DTCs P0112 or P0113 are set and IAT is available, then the default TFT is equal to IAT. |
| • | Any Intake Air Temperature (IAT) DTCs P0112 or P0113 are set or IAT is NOT available, then the default TFT is equal to 90°C (194°F). |
| 4. | If the Engine Run Time is greater than 300 seconds and No Intake Air Temperature (IAT) DTCs P0112 or P0113 are set and IAT is available and Engine Coolant Temperature (ECT) is between 40 and 125°C (104 and 257°F) and: |
| • | IAT at startup is less than 15°C (59°F), then the default TFT is equal to the Engine Coolant Temperature (ECT) plus 5°C (8°F). |
| • | IAT at startup is greater than 35°C (95°F), then the default TFT is equal to the Engine Coolant Temperature (ECT) plus 10°C (16°F). |
| • | IAT at startup is between 15 and 35°C (59 and 95°F), then the default TFT is equal to the Engine Coolant Temperature (ECT). |
| 5. | If the Engine Run Time is greater than 300 seconds and any Intake Air Temperature (IAT) DTCs P0112 or P0113 are set or IAT is NOT available, then the default TFT is equal to the Engine Coolant Temperature (ECT). |
| 6. | If the Engine Run Time is greater than 300 seconds and ECT is less than 40°C (104°F) or more, then the default TFT is equal to 60°C (140°F). |
| • | The VCM freezes shift adapts from being updated. |
| • | DTC P0711 stores in VCM history. |
Conditions for Clearing the DTC
| • | A scan tool can clear the DTC from the VCM history. The VCM clears the DTC from the VCM history if the vehicle completes 40 warm-up cycles without a failure reported. |
| • | The VCM cancels the DTC default actions when the fault no longer exists and the ignition is OFF long enough in order to power down the VCM. |
Diagnostic Aids
DTC P0218 may set approximately 600 seconds after DTC P0711 has set. Follow the diagnostic table for DTC P0711 before proceeding to the diagnostic table for DTC P0218. Repairing the condition that caused DTC P0711 will likely eliminate DTC P0218.
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 light is used as a resistor in the circuit.
-
This step determines if the VCM or the TFT sensor is causing a steady, unchanging TFT reading.
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 (4.3L) or Powertrain On Board Diagnostic (OBD) System Check (5.0L, 5.7L) in Engine Controls | |||||
2 | Perform the transmission fluid checking procedure. Refer to Transmission Fluid Check . Did you perform the fluid checking procedure? | -- | Go to Transmission Fluid Check | |||||
3 |
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 VCM.
Did either of the fail conditions occur? | -- | Go to Diagnostic Aids | |||||
4 | Did the Scan Tool display a condition in which the TFT does not change by more than the specified value in 409 seconds since startup? | 1.50°C (2.7°F) | ||||||
Refer to Automatic Transmission Inline Harness Connector End View . Does the TFT change by more than the specified value? | 20°C (36°F) | |||||||
Does the Scan Tool display the same condition as in Step 4? | -- | |||||||
7 |
Refer to General Electrical Diagnosis in Wiring Repairs. Refer to Wiring Repairs in Wiring Repairs. Did you find an intermittent open or short condition? | -- | ||||||
8 |
Refer to General Electrical Diagnosis in Wiring Repairs. Did you find an intermittent open or short condition? | -- | ||||||
9 | Replace the A/T Wiring Harness Assembly. Is the replacement complete? | -- | -- | |||||
10 | Replace the TFT Sensor (the sensor is a part of the TFP Manual Valve Position Switch). Refer to Valve Body and Pressure Switch Replacement. Is the replacement complete? | -- | -- | |||||
11 | Replace the VCM. Refer to VCM Replacement/Programming (4.3L) or VCM Replacement/Programming (5.0L, 5.7L) in Engine Controls. Is the replacement complete? | -- | -- | |||||
12 | In order to verify your repair, perform the following procedure:
Has the test run and passed? | -- | System OK |
