P0711

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 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 are set.
^ No Vehicle Speed (VSS) sensor DTCs P0502 or P0503 are set.
^ No Automatic Transmission Input Speed (A/T ISS) sensor DTCs P0716 or P0717 are set.
^ 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) after two consecutive trips with a failure reported.
^ 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).

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. Inspect the wiring for poor electrical connections at the transmission 2-way connector. Look for the following problems:

- A bent terminal
- A backed out terminal
- A damaged terminal
- Poor terminal tension
- A chafed wire

^ 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.

2. This step ensures that the transmission fluid is at the proper level. Low fluid may cause this DTC to set.
3. You must clear the DTC before running this test. This test is best performed from a cold start. If the DTC does not set. road test the vehicle as instructed in step 12. If the TFT defaults to a calibrated value, proceed to step 4.
4. Perform this test in order to detect an intermittent problem. If the transmission fluid is warm, the voltage will rise slowly. A rapid rise or drop in voltage, caused by massaging the harness, indicates an open or short.
5. Perform this step in order to detect an intermittent problem in the transmission harness. The resistance value must be recorded as soon as the ohmmeter is set on MAX. If an open or short to ground occurs the display will indicate a resistance higher than the recorded value. You must use J 39200 DVOM.
6. This step detects a short together of circuits 1227 and 452. The ohmmeter displays a resistance lower than the recorded value.