Circuit Description
The Automatic Transmission Fluid Temperature (TFT) Sensor is a thermistor (temperature sensitive resistor). The TFT Sensor is part of the 4L80-E Automatic Transmission Wiring Harness Assembly (A/T Wiring Harness Assy). The TFT Sensor receives a 5 volt reference signal from the Vehicle Control Module (VCM) on circuit 1227. When the fluid temperature is low, the TFT Sensor has a high resistance and the VCM detects a high voltage on circuit 1227. As fluid temperature rises, the TFT Sensor resistance gradually decreases and the VCM senses a lower voltage on circuit 1227.
If the VCM detects no change in the TFT Sensor resistance or unrealistic changes in a short amount of time in the TFT Sensor resistance (multiple changes within seconds), then DTC P0711 sets. DTC P0711 is a type D DTC. For California emissions vehicles, DTC P0711 is a type B DTC.
Conditions for Setting the DTC
| • | No Engine Coolant Temperature (ECT) DTCs P1117 or P1118 |
| • | No OSS Sensor DTC P0502 |
| • | No A/T ISS Sensor DTC P0716 or P0717 |
| • | No A/T Component Slipping DTC P1870 |
| • | The system voltage is greater than 10.0 and less than 16.0 volts. |
| • | The engine is running greater than 475 RPM for at least 30 seconds. |
| • | The Engine Coolant Temperature (ECT) is greater than 80°C (185°F). |
| • | The TFT is -40 to +21°C (-40 to +70°F) at start up. |
| • | The Engine Coolant Temperature (ECT) has changed at least 50°C (122°F) since start up. |
| • | The vehicle speed is greater than 5 mph for at least 900 seconds (15 minutes). |
| • | The TCC slip speed is greater than 80 RPM for at least 850 seconds (14 minutes). |
| • | DTC P0711 sets if all of the above conditions have been met and one of the following conditions exist: |
| - | No TFT change: The TFT has not changed more than 2.25°C (4°F), in more than 250 seconds (4 minutes). |
| - | An unrealistic temperature change: The TFT has changed more than 20°C (68°F) 14 times in 7 seconds. |
Action Taken When the DTC Sets
| • | The VCM uses a TFT default value of 140°C (280°F). |
| • | The VCM freezes shift adapts. |
| • | The VCM illuminates the Malfunction Indicator Lamp (MIL) on California emissions vehicles. |
Conditions for Clearing the MIL/DTC
| • | For California Emissions only, the VCM turns off the MIL after three consecutive ignition cycles without a failure reported. |
| • | 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 to power down the VCM. |
Diagnostic Aids
| • | When diagnosing for an intermittent short or open, massage the wiring harness while watching the test equipment for a change. |
| • | First diagnose and clear any engine DTCs or TP Sensor DTCs that are present. Then inspect for any transmission DTCs that may have reset. |
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.
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This step verifies that the vehicle sets DTC P0711.
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The 12 volt test lamp is used as a fixed resistance.
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This step ensures that the VCM monitors circuit 1227.
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The TFT Sensor is part of the A/T Wiring Harness Assy.
Step | Action | Value(s) | Yes | No | ||||
|---|---|---|---|---|---|---|---|---|
1 | Was the Powertrain On-Board Diagnostic (OBD) System Check performed? | -- | Go to A Powertrain On Board Diagnostic (OBD) System Check | |||||
Perform the Transmission Fluid Check . Did you perform the fluid checking procedure? | -- | Go to Transmission Fluid Check | ||||||
Important: Before clearing the DTCs, use the scan tool in order to record the Failure Records for reference. The Clear Info function will erase the data.
Did either of the fail conditions occur? | -- | Fault is not present. Refer to Diagnostic Aids | ||||||
4 | Did the scan tool display an unrealistic change? | -- | ||||||
Does the scan tool TFT display an unrealistic change? | -- | |||||||
Is the scan tool TFT the same as in step 4? | -- | |||||||
7 | Replace the VCM. Refer to VCM Replacement/Programming , Section 6. Is the replacement complete? | -- | -- | |||||
Replace the A/T Wiring Harness Assy. Refer to Interior Wiring Harness Replacement, in On-vehicle Service. Is the replacement complete? | -- | -- | ||||||
9 | In order to verify your repair, perform the following procedure:
Has the test run and passed? | -- | System OK |
