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 up, the sensor resistance decreases. This diagnositc 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 Powertrain Control Module (PCM) detects an intermittent voltage or no voltage change in the TFT sensor circuit, then DTC P0711 sets. DTC P0711 is a Type B DTC.
Conditions for Setting the DTC
| • | No ECT DTCs P0116, P0117, P0118, P1114 or P1115. |
| • | No VSS DTCs P0502 or P0503. |
| • | No A/T ISS DTCs P0716 or P0717. |
| • | The system voltage is 10-17 volts. |
| • | The transmission fluid temperature is -37 to 149°C (-35 to 300°F). |
| • | The transmission fluid temperature at start-up is -40 to 21°C (-40 to 70°F). |
| • | The engine run time is greater than 15 minutes. |
| • | The vehicle speed is greater than 24 km/h (15 mph) for 2 minutes and 30 seconds. |
| • | The TCC slip is greater than 4 RPM for 1 second or greater. |
| • | The engine coolant temperature is greater than 70°C (158°F). |
| • | The engine coolant temperature has changed by 50°C (90°F) since start-up. |
Fail case 1: The change in transmission fluid temperature is less than 1.5°C (2°F) since start-up for 4 minutes and 14 seconds.
Fail case 2: The change in transmission fluid temperature is greater 20°C (36°F) within 200 milliseconds and 14 times within 7 seconds.
Action Taken When the DTC Sets
| • | The PCM illuminates the Malfunction Indicator Lamp (MIL). |
| • | If any engine coolant temperature sensor codes set, the PCM substitutes a transmission fluid temperature default value of 132°C (269°F). |
| • | If the engine coolant temperature is greater than 115°C (239°F), the PCM substitutes a transmission fluid temperature default value of 132°C (269°F). This enables Transmission Hot Mode. The transmission remains in Hot Mode until the engine coolant temperature drops below 110°C (230°F). |
| • | If the engine run time is less than 3 minutes, the PCM substitutes the intake air temperature for the transmission fluid temperature value at ignition ON. |
| • | If the engine coolant temperature is 45-115°C (113-239°F), the transmission fluid default temperature equals ECT-10°C when the intake air temperature is less than 27°C (81°F) at ignition ON. If the intake air temperature is greater than 27°C (81°F) at ignition ON, the transmission fluid default temperature equals ECT+10°C. |
| • | If the engine run time is greater than 3 minutes and the engine coolant temperature is less than 45°C (113°F), the PCM substitutes a transmission fluid temperature default value of 12°C (54°F). |
| • | DTC P0711 is stored in the PCM history. |
Conditions for Clearing the MIL/DTC
| • | The PCM turns OFF the MIL after three consecutive trips without a failure reported. |
| • | 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. Inspect the wiring for poor electrical connections at the transmission 20-way connector. Look for the following problems: |
| - | A bent terminal |
| - | A backed out terminal |
| - | A damaged terminal |
| - | Poor terminal tension |
| - | A chafed wire |
| - | A broken wire inside the insulation |
| - | Moisture intrusion |
| • | 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, 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? | -- | Go to A Powertrain On Board Diagnostic (OBD) System Check | |||||
2 | Has the transmission fluid checking procedure been performed? | -- | 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? | -- | ||||||
4 | Did the scan tool display a condition in which the TFT does not change by more than the specified value in 4 minutes and 14 seconds since startup? | 1.5°C (2°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 4 minutes and 14 seconds since startup? | 1.5°C (2°F) | |||||||
7 |
Inspect circuits 1227 and 452 of the engine wiring harness for an intemittent open or short condition. Repair the circuits if necessary. Refer to Electrical Diagnosis, Section 8. Did you find and correct the condition? | -- | ||||||
8 | Inspect the Automatic Transmission Wiring Harness assembly for an intemittent open or short condition in circuits 1227 and 452. Refer to Electrical Diagnosis, Section 8. Did you find the condition? | -- | ||||||
9 | Replace the Automatic Transmission Wiring Harness. Refer to Automatic Transmission Wiring Harness Replacement. Is the replacement complete? | -- | -- | |||||
10 | Replace the Transmission Fluid Temperature Sensor. Refer to TFT Sensor Replacement, in On-Vehicle Service. Is the replacement complete? | -- | -- | |||||
11 | Replace the PCM. Refer to PCM Replacement/Programming Section 6. Is the replacement complete? | -- | -- | |||||
12 | In order to verify your repair, perform the following procedure:
Has the test run and passed? | -- | System OK |
