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 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 ECT DTCs P0116, P0117, P0118, P1114 or P1115 are set. |
| • | No VSS DTCs P0502 or P0503 are set. |
| • | No System Voltage Malfunction DTC P0560 is set. |
| • | No TFT DTCs P0712 or P0713 are set. |
| • | No A/T ISS DTCs P0716 or P0717 are set. |
| • | The transmission fluid temperature at start-up is 0-100°C (32-212°F). |
| • | The engine run time is more than 5 minutes. |
| • | The vehicle speed is greater than 8 km/h (5 mph) for 2 minutes. |
| • | The TCC slip is greater than 48 RPM for 2 minutes. |
| • | The engine coolant temperature is more than 0°C (32°F). |
| • | The engine coolant temperature has changed by 40°C (72°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 than 10°C (18°F) within 1 second and 10 times within 10 seconds.
Action Taken When the DTC Sets
| • | 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 110°C (230°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 105°C (221°F). |
| • | If the engine run time is less than 5 minutes, the PCM substitutes the intake air temperature for the transmission fluid temperature value at ignition ON. |
| • | If the engine coolant temperature is 70-110°C (158-230°F), the transmission fluid default temperature equals ECT-10°C when the intake air temperature is less than 80°C (176°F) at ignition ON. If the intake air temperature is greater than 80°C (176°F) at ignition ON, the transmission fluid default temperature equals ECT+10°C. |
| • | If none of the above conditions exist, the PCM substitutes a transmission fluid temperature default value of 80°C (176°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 20-way connector. Look for the following conditions: |
| - | 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 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 ensures that the Powertrain On-Board Diagnostic System Check was performed.
-
This Step ensures that the transmission fluid is at the proper level. Low fluid may cause this DTC to set.
-
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.
-
Perform this test in order to detect an intermittent condition. 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 shorted condition.
-
Perform this Step in order to detect an intermittent condition 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 condition occurs the display will indicate a resistance higher than the recorded value. You must use J 39200 DVOM.
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This Step detects a short together of circuits 1227 and 452. The ohmmeter displays a resistance lower than the recorded value.
-
This Step makes the appropriate repair to the engine wiring harness.
-
This Step inspects the transmission harness for an open, short to ground, or short together condition.
-
This Step replaces the Automatic Transmission Wiring Harness, if any conditions were found in Step 8.
-
This Step replaces the TFT sensor. The sensor may be skewed.
-
This Step replaces the PCM. The component and circuitry have been tested.
Step | Action | Value(s) | Yes | No | ||||
|---|---|---|---|---|---|---|---|---|
Was the Powertrain On-Board Diagnostic (OBD) System Check performed? | -- | Go to A Powertrain On Board Diagnostic (OBD) System Check | ||||||
Has the transmission fluid checking procedure been performed? | -- | 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. Does the TFT Sensor Temperature default to a calibrated value? | -- | |||||||
4 |
Does the TFT voltage indicate an unrealistic change when you massage the harness and connectors? | -- | ||||||
In the MAX position, does the ohmmeter display a value higher than the recorded value? | -- | |||||||
6 | In the MIN position, does the ohmmeter display a value lower than the recorded value | -- | -- | |||||
Repair circuits 1227 or circuit 452 of the engine harness. Refer to Electrical diagnosis, Section 8. Did you find and correct a problem? | -- | |||||||
Inspect the Automatic Transmission Wiring Harness. Did you find a short to ground, short together, or open condition? | -- | |||||||
Replace the Automatic Transmission Wiring Harness. Refer to Automatic Transmission Wiring Harness Replacement. Is the replacement complete? | -- | -- | ||||||
Replace the Transmission Fluid Temperature Sensor. Refer to TFT Sensor Replacement. Is the replacement complete? | -- | -- | ||||||
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 |
