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, in two consecutive trips, then DTC P0711 sets. DTC P0711 is a Type D DTC.
Conditions for Setting the DTC
| • | No VSS DTCs P0502 or P0503 are set. |
| • | The System Voltage is 9-16 volts. |
| • | The TFT sensor voltage is 0.2-4.92 volts. |
| • | The transmission fluid temperature at start-up is -40 to 21°C (-40 to 69°F). |
| • | The engine run time is more than 5 minutes. |
| • | The vehicle speed is greater than 8 km/h (5 mph) for greater than 409 seconds. |
| • | 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 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 7 minutes continuous.
Fail 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 does not illuminate the Malfunction Indicator Lamp (MIL). |
| • | The PCM disables shift adapts. |
| • | 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 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 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 |
| - | Moisture Intrusion |
| • | Test the TFT sensor at various temperature levels to evaluate the possibility of a skewed (mis-scaled) sensor. Refer to Temperature vs Resistance Chart. |
| • | 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 determines if the condition exists in the wiring or a component.
-
This step determines if the condition exists in the engine harness or the transmission harness.
-
This step determines if a condition exists with the PCM or TFT Sensor.
Step | Action | Value(s) | Yes | No | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
1 | Was the Powertrain On-Board Diagnostic (OBD) System Check performed? | -- | Go to Powertrain On Board Diagnostic (OBD) System Check in Engine Controls | |||||||
2 | Did you perform the transmission fluid checking procedure? | -- | Go to Transmission Fluid Check | |||||||
Important:: Before clearing the DTCs, use the Scan Tool in order to record the Freeze Frame and Failure Records for reference. The Clear Info function will erase the data. Does the transmission fluid temperature fluctuate by more than the specified value? | 20° in 0.20 seconds | |||||||||
4 | Let the vehicle run for at least 7 minutes. Does the transmission fluid temperature rise more than the specified value? | 1.5°C (2.7°F) | Go to Diagnostic Aids | |||||||
Important:: Additional DTCs will set. Does the TFT fluctuate by more than the specified value? | 20°C (36°F) | |||||||||
Important:: Additional DTCs will set. Is the TFT the same as in step 3? | -- | |||||||||
7 | Check circuits 808 (BLK) and 1227 (YEL/BLK) of the engine harness for an intermittent open or short to ground. Refer to General Electrical Diagnosis in Wiring Systems. Was the condition found and corrected? | -- | ||||||||
8 | Check circuits 452 (GRY) and 1227 (BRN) of the transmission harness for an intermittent open or short to ground. Refer to General Electrical Diagnosis in Wiring Systems. Was the condition found and corrected? | -- | ||||||||
9 | Replace the Automatic Transmission Wiring Harness. Refer to Solenoids and Wiring Harness Replacement . Is the replacement complete? | -- | -- | |||||||
10 | Inspect the PCM connector C2 (CLR) for bent, damaged or backed out connector pins. Was the condition found and corrected? | -- | ||||||||
11 | Replace the PCM. Refer to Powertrain Control Module Replacement/Programming in Engine Controls. Is the replacement complete? | -- | -- | |||||||
12 | Replace the Transmission Fluid Temperature Sensor. Refer to Fluid Temperature Sensor Replacement . Is the replacement complete? | -- | -- | |||||||
13 | In order to verify your repair, perform the following procedure:
Has the test run and passed? | -- | System OK |
