Circuit Description
The Automatic 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. This diagnostic monitors the TFT circuit. The circuit may be functional, but not in the normal operating range. This diagnostic indicates stuck, erratic, intermittent, or skewed values, indicating poor system performance. The TFT range is -40 to +151°C (-40 to +305°F).
When the PCM detects an intermittent voltage or no voltage change in the TFT sensor circuit, then DTC P0711 sets. DTC P0711 is a type D DTC.
Conditions for Setting the DTC
| • | No VSS DTCs P0502 or P0503. |
| • | No A/T ISS DTCs P0716 or P0717. |
| • | The transmission fluid temperature at start-up is -40 to 21°C (-40 to 70°F). |
| • | System voltage is 9-16 volts. |
| • | The engine run time is greater than 1 minute and 40 seconds. |
| • | The vehicle speed is greater than 8 km/h (5 mph) for 15 minutes cumulatively. |
| • | The TCC slip is greater than 120 RPM for 6 minutes and 49 seconds cumulatively. |
| • | The engine coolant temperature is greater than 70°C (158°F). |
| • | The engine coolant temperature has changed by more than 50°C (90°F) since start-up. |
Failure Criteria
Case 1
The change in transmission fluid temperature is less than 1.5°C (2°F) since start-up for 20 seconds.
Case 2
The change in transmission fluid temperature is greater than 20°C (36°F) within 200 milliseconds; 14 times within 7 seconds.
Action Taken When the DTC Sets
| • | The PCM does not illuminate the Malfunction Indicator Lamp (MIL). |
| • | The PCM freezes shift adapts from being updated. |
| • | The PCM calculates a default transmission fluid temperature based on engine coolant temperature, manifold air temperature, and engine run time. |
| • | DTC P0711 is stored in the PCM history. |
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 for poor electrical connections at the PCM, the transmission 20-way connector and the TFP Val. Position Sw. 6-way connector 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. |
| • | When diagnosing for an intermittent short or open condition, massage the wiring harness while watching the test equipment for a change. |
| • | Inspect the transmission 20-way connector for transmission fluid. |
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 PCM 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? | -- | ||||||
2 | Have you performed the transmission fluid checking procedure? | -- | Go to Transmission Fluid Check | |||||
3 |
Important: Before clearing the DTCs, use the scan tool in order to record the Freeze Frame and Failure Records for reference. Using the Clear Info function will erase the stored Freeze Frame and Failure Records from the PCM.
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 80 seconds since startup? | 1.5°C (2.7°F) | ||||||
Does the TFT change by more than the specified value? | 20°C (36°F) | |||||||
Did the scan tool display a condition in which the TFT does not change by more than the specified value in 80 seconds since startup? | 1.5°C (2.7°F) | |||||||
7 | Inspect circuits 1227 and 407 of the engine wiring harness for an intermittent open or short condition. Repair the circuits if necessary. Refer to General Electrical Diagnosis . Did you find and correct the condition? | -- | ||||||
8 | Inspect the automatic transmission wiring harness for an intermittent open or short condition in circuits 1227 and 452. Refer to General Electrical Diagnosis . Did you find the condition? | -- | ||||||
9 | Replace the automatic transmission wiring harness. Refer to the Transmission Unit Repair Manual, 4T40-E Section. Is the replacement complete? | -- | -- | |||||
10 | Replace the TFT Sensor (this is part of the TFP Valve Position Switch). Refer to the Transmission Unit Repair Manual, 4T40-E Section. Is the replacement complete? | -- | -- | |||||
11 | Replace the PCM. Refer to PCM Replacement/Programming . Is the replacement complete? | -- | -- | |||||
12 | In order to verify your repair, perform the following procedure:
Has the test run and passed? | -- | System OK |
