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 +304°F).
If 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 Setting the DTC
| • | No VSS DTCs P0502 or P0503 are set. |
| • | No Transmission Component Slipping DTC P1870 is set. |
| • | The System Voltage is 10-16 volts. |
| • | The transmission fluid temperature at start-up is -40 to 21°C (-40 to 70°F). |
| • | The engine run time is more than 5 minutes. |
| • | The vehicle speed is greater than 8 km/h (5 mph) for 7 minutes cumulative. |
| • | The TCC slip is greater than 120 RPM for 7 minutes cumulative. |
| • | The engine coolant temperature is more than 70°C (158°F). |
| • | The engine coolant temperature has changed more than 50°C (90°F) since start-up. |
| • | All of the above conditions are met and one of the following fail cases is true. |
| - | Case 1: The change in transmission fluid temperature is less than 1.5°C (2°F) since start-up for 6 minutes and 49 seconds. |
| - | Case 2: The change in transmission fluid temperature is greater than 20°C (36°F) within 0.2 seconds and 14 times within 7 seconds. |
Action Taken When the DTC Sets
| • | The PCM illuminates the Malfunction Indicator Lamp (MIL) after two consecutive ignition cycles with a failure reported. |
| • | If the Engine Run Time is less than 3 minutes and: |
| - | Intake Air Temperature (IAT) DTC P0112, P0113, P1111, or P1112 is set, then the default Automatic Transmission Fluid Temperature (TFT) is 0°C (32°F). |
| - | No IAT DTC is set, then the default TFT is set to the IAT saved at start up. |
| • | If the engine run time is greater than 3 minutes and an Engine Coolant Temperature (ECT) DTC P0117, P0118, P1114, or P1115 is set, then the default TFT is 131°C (268°F). |
| • | If the engine run time is greater than 3 minutes, no ECT DTC is set, and: |
| - | The ECT is less than 45°C (113°F), then the default TFT is 12°C (54°F). |
| - | The ECT is greater than 115°C (239°F), then the default TFT is 131°C (268°F). |
| - | The ECT is 45-115°C (113-239°F) and: |
| • | The IAT DTC P0112, P0113, P1111, or P1112 is set, then the default TFT is set to equal the ECT. |
| • | The IAT at start up is less than 0°C (32°F), then the default TFT is set to ECT minus 10°C (18°F). |
| • | The IAT at start up is greater than 28°C (82°F), then the default TFT is set to ECT plus 10°C (18°F). |
| • | The IAT at start up is 0-28°C (32-82°F), then the default TFT is set to equal ECT. |
Conditions for Clearing the MIL/DTC
| • | The PCM turns OFF the MIL after three consecutive ignition cycles 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 |
| • | Test the TFT sensor at various temperature levels to evaluate the possibility of a skewed (mis-scaled) sensor. Refer to Temperature vs Resistance . |
| • | 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.
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This test is best performed from a cold start. If the TFT does not default, inspect for intermittent problems. If the TFT defaults to a calibrated value, proceed to Step 4.
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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.
-
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 DMM.
Step | Action | Value(s) | Yes | No | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
1 | Was the Powertrain On-Board Diagnostic (OBD) System Check performed? | -- | ||||||||
2 | Has the transmission fluid checking procedure been performed? | -- | Go to Fluid Check Procedure | |||||||
Important: Before clearing the DTCs, use the scan tool in order to record the Failure Records for reference. Using the Clear Info function will erase the stored Failure Records from the PCM. Does the TFT Sensor Temperature default to a calibrated value? | -- | Go to Diagnostic Aids | ||||||||
Does the TFT voltage indicate a change greater than indicated, in less than 1 second when you massage the harness and connectors? | 0.200 volts | |||||||||
In the MAX position, does the ohmmeter display a value higher than the recorded value? | -- | |||||||||
6 | Inspect circuits 1227 or circuit 452 of the engine harness. Refer to Electrical Diagnosis, Section 8. Did you find a short together or open? | -- | ||||||||
7 | In the MIN position, does the ohmmeter display a value lower than the recorded value? | -- | -- | |||||||
8 | Repair circuits 1227 or circuit 452 of the Automatic Transmission (A/T) Wiring Harness. Refer to Electrical diagnosis, Section 8. Did you find a short to ground or a short together? | -- | ||||||||
9 | Inspect the Automatic Transmission (A/T) Wiring Harness. Did you find an open? | -- | -- | |||||||
10 | Replace the Automatic Transmission (A/T) Wiring Harness. Refer to Automatic Transmission Wiring Harness Replacement, in On-Vehicle Service. Is the replacement complete? | -- | -- | |||||||
11 | Replace the Transmission Fluid Temperature Sensor. Refer to TFT Sensor Replacement, in On-Vehicle Service. Is the replacement complete? | -- | -- | |||||||
12 | Replace the PCM. Refer to Powertrain Control Module Replacement/Programming section 6. Is the replacement complete? | -- | -- | |||||||
13 | In order to verify your repair, perform the following procedure:
Has the test run and passed? | -- | System OK |
