The 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, the sensor resistance decreases. The TFT range is -40 to +150°C (-40 to +302°F).
The PCM provides a 5 volt reference through a fixed series resistor to the TFT circuit, and monitors the voltage after the resistor, as the voltage drop (signal) across the circuit.
If the PCM detects a large, rapid, fluid temperature change, or essentially no change from a cold startup, then DTC P0711 sets. DTC P0711 is a type D DTC.
• | No VSS DTCs P0502 or P0503. |
• | System voltage is 10-16 volts. |
• | No Transmission Component Slipping DTC P1870. |
• | The TFT at start up is -40 to 21°C (-40 to 69°F) |
• | The engine run time is 5 minutes or more. |
• | The vehicle speed is 8 km/h (5 mph) or more for 7 minutes or more, cumulative this ignition cycle. |
• | The TCC slip speed is 120 RPM or more for 7 minutes, cumulative this ignition cycle. |
• | The ECT is 70°C (158°F) or more. |
• | The ECT has changed 50°C (90°F) or more since start up. |
• | The TFT voltage is 0.20-4.92 volts. |
All of the above must be true and one of the following fail cases must be true:
• | Fail Case 1 |
The change in TFT is 1.5°C (2.7°F) or less since start up for 7 minutes or more. |
• | Fail Case 2 |
The change in TFT is 20°C (36°F) or more within 0.2 seconds for 14 times or more within 7 seconds. |
• | The PCM does not illuminate the Malfunction Indicator Lamp (MIL). |
• | The PCM calculates a transmission fluid default temperature as follows: |
• | If any engine coolant temperature sensor codes are set, the PCM substitutes a transmission fluid temperature default value of 131°C (268°F). |
• | If the engine coolant temperature is greater than 115°C (239°F), the PCM substitutes a transmission fluid temperature default value of 131°C (268°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 startup except if any inlet air temperature codes are set, the PCM sets default temperature to 0°C (32°F). |
• | If engine run time is greater than 3 minutes and 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 0°C (32°F) at startup. If the intake air temperature is greater than 28°C (82°F) at startup, the transmission fluid default temperature equals ECT+10°C. If the intake air temperature (IAT) is 0-28°C (32-82°F) or any IAT DTC codes are set then transmission fluid default temperature is set to coolant temperature. |
• | If the engine run time is greater than 3 minutes and the engine coolant temperature is less than 45°C (113°F), the transmission fluid default temperature is set to 12°C (54°F). |
• | 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. |
• | Inspect the wiring at the PCM, the transmission connector and all other circuit connecting points for the following conditions: |
- | A bent terminal |
- | A backed out terminal |
- | A damaged terminal |
- | Poor terminal tension |
- | A chafed wire |
- | A broken wire inside the insulation |
- | Moisture intrusion |
- | Corrosion |
• | Test the TFT sensor at various temperature levels in order to evaluate the possibility of a skewed (mis-scaled) sensor. |
• | Refer to Temperature vs Resistance . |
• | When diagnosing for an intermittent short or open condition, massage the wiring harness while watching the test equipment for a change. |
The numbers below refer to the step numbers on the diagnostic table.
This step tests for proper A/T fluid level and condition.
This step verifies which condition has set DTC P0711.
The 12-volt test lamp is used as a fixed resistance.
This step ensures that the PCM monitors circuit 1227.
Step | Action | Value(s) | Yes | No | ||||||
---|---|---|---|---|---|---|---|---|---|---|
1 | Was the Powertrain On-Board Diagnostic (OBD) System Check performed? | -- | ||||||||
Perform the Transmission Fluid Checking Procedure. 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. Using the Clear Info function will erase the stored Freeze Frame and Failure Records from the PCM.
Did either of the fail conditions occur? | -- | Go to Diagnostic Aids | ||||||||
4 | Did the scan tool display unrealistic TFT voltage fluctuations? | -- | ||||||||
Does the scan tool display an unrealistic TFT voltage fluctuation? | -- | |||||||||
Is the scan tool TFT the same as before disconnecting the 7-way connector? | -- | |||||||||
7 | Replace the PCM. Refer to Powertrain Control Module Replacement/Programming in Engine Controls. Is the replacement complete? | -- | -- | |||||||
8 | Replace the TFT Sensor. Refer to Fluid Temperature Sensor Replacement. Is the replacement complete? | -- | -- | |||||||
9 | Perform the following procedure, to verify your repair:
Has the test run and passed? | -- | System OK |