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 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 B DTC.
Conditions for Running 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. |
| • | 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. |
Conditions for Setting the DTC
One of the following conditions occurs:
| • | The change in transmission fluid temperature is less than 1.5°C (2°F) since start-up for 4 minutes and 14 seconds. |
| • | 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 illuminates the malfunction indicator lamp (MIL) during the second consecutive trip in which the Conditions for Setting the DTC are met. |
| • | The PCM calculates a default transmission fluid temperature based on engine coolant temperature, intake air temperature and engine run time. |
| • | The PCM stores DTC P0711 in PCM history during the second consecutive trip in which the Conditions for Setting the DTC are met. |
Conditions for Clearing the MIL/DTC
| • | The PCM turns OFF the MIL during the third consecutive trip in which the diagnostic test runs and passes. |
| • | A scan tool clears the DTC from PCM history. |
| • | The PCM clears the DTC from PCM history if the vehicle completes 40 warm-up cycles without an emission-related diagnostic fault occurring. |
| • | The PCM cancels the DTC default actions when the fault no longer exists and the ignition switch is OFF long enough in order to power down the PCM. |
Diagnostic Aids
| • | Inspect the wiring at the PCM, the transmission 20-way connector, and the TFT sensor 2-way connector for the following conditions: |
| - | A backed out terminal |
| - | A damaged terminal |
| - | Reduced 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. |
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 | Was the Transmission Fluid Checking Procedure 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. Using the Clear Info function erases the Freeze Frame and Failure Records from the PCM.
Did either of the 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 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 intermittent open or short condition. Refer to General Electrical Diagnosis in Wiring Systems. Was a condition found? | -- | ||||||
8 | Inspect circuits 1227 and 452 of the automatic transmission wiring harness for an intermittent open or short condition. Refer to General Electrical Diagnosis in Wiring Systems. Was a condition found? | -- | ||||||
9 | Repair the wiring as necessary. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | -- | |||||
10 | Replace the automatic transmission wiring harness. Refer to Unit Repair. Is the replacement complete? | -- | -- | |||||
11 | Replace the TFT sensor. Refer to Unit Repair. Is the replacement complete? | -- | -- | |||||
12 | Replace the PCM. Refer to Powertrain Control Module Replacement/Programming in Engine Controls. Is the replacement complete? | -- | -- | |||||
13 | Perform the following procedure in order to verify the repair:
Has the test run and passed? | -- | System OK |
