GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The transmission fluid temperature (TFT) sensor is a part of the pressure switch manifold (PSM) assembly, and is located in the transmission oil pan. The TFT sensor is a thermistor, which changes value based on the temperature of the transmission fluid. The sensor has a negative-temperature coefficient. This means that as the temperature increases, the resistance decreases, as the temperature decreases the resistance increases. The transmission control module (TCM) supplies a 5 volt reference voltage signal to the TFT sensor and measures the voltage drop in the circuit. When the transmission is cold, the sensor resistance is high and the TCM detects high signal voltage. As the fluid temperature warms to a normal operating temperature, the resistance becomes less and the signal voltage decreases. The TCM uses this information to control shift quality and torque converter clutch (TCC) apply.

DTC P0711 is a type B DTC.

Conditions for Running the DTC

    • DTC P0712, P0713, P0716, P0717, P0721, and P0722 are not active.
    • The components are powered and ignition voltage is greater than 9.0 volts and less than 18 volts.
    • Engine speed is greater than 200 RPM and less than 7,500 RPM for 5 seconds.
    • The engine has been running for 2 seconds.
    • Engine speed is above 450 RPM and output speed is above 100 RPM.
    • The TFT is in the range of -35°C to +149°C (-31°F to +300°F).

Conditions for Setting the DTC

DTC P0711 sets when the TCM detects one of the following conditions:

    • The TCM detects a temperature change that is below a set limit when compared to samples of the minimum and maximum temperature values.
    • The TFT has an unrealistic temperature change of greater than 10°C (50°F) for 10 occurrences.
    • The temperature from startup decreases 40°C (104°F) or greater within a duration of 6 seconds or greater.

Action Taken When the DTC Sets

    • The TCM illuminates the malfunction indicator lamp (MIL) during the second consecutive trip in which the Conditions for Setting the DTC are met.
    • The TCM freezes shift adapts.
    • The TCM records the operating conditions when the Conditions for Setting the DTC are met. The TCM stores this information as Failure Records.
    • The TCM stores DTC P0711 in TCM history.
    • The TCM inhibits TCC engagement.

Conditions for Clearing the DTC

A scan tool can clear the code from TCM history. The TCM automatically clears the DTC from TCM history if the vehicle completes 40 warm-up cycles without failure.

Diagnostic Aids

    • The TFT should rise steadily during warm-up cycles, then stabilize.
    • DTC P0218 may set after DTC P0711 has set. Follow the diagnostic table for DTC P0711 before proceeding to the diagnostic for DTC P0218.
    • Inspect the wiring for poor electrical connections at the TCM. Inspect 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
    • When diagnosing for an intermittent short or open, massage the wiring harness while watching the test equipment for a change.
    • You may have to drive the vehicle in order to experience a condition.
    • An open condition at circuit 2762 may allow a ground path internally through circuit 2471. If this occurs, the TCM sees a temperature that appears to be within normal operation, approximately -22°C (-7.6°F), and initially a code will not be set. However, the transmission will still inhibit shift adapts and TCC operation. It may take several minutes before P0711 code is set to indicate a failure.

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. This step tests 5 volt reference.

  2. This step tests the TFT sensor and internal wiring harness.

  3. This step tests the resistance of the TFT sensor.

Step

Action

Value

Yes

No

Schematic Reference: Automatic Transmission Controls Schematics

1

Did you perform the Diagnostic System Check - Automatic Transmission?

--

Go to Step 2

Go to Diagnostic System Check - Automatic Transmission

2

Measure the transmission fluid level.

Refer to Transmission Fluid Check .

Is the transmission fluid level correct?

--

Go to Step 3

Go to Transmission Fluid Check

3

  1. Install the scan tool.
  2. Turn ON the ignition, with the engine OFF.
  3. Important: Before clearing the DTC, use the scan tool in order to record the Freeze Frame and Failure Records for reference. The Clear Info function will erase the data.

  4. Record the DTC Freeze Frame and Failure Records.
  5. Clear the DTC.
  6. Select TFT on the scan tool.
  7. Drive the vehicle and look for an unrealistic TFT reading.

Is the TFT reading at or below the specified value?

1.5°C (2.7°F)

Go to Step 4

Go to Diagnostic Aids

4

  1. Turn the ignition OFF.
  2. Disconnect C2 connector (RED) at the TCM.
  3. Install the J 39700 breakout box and the J 43799 breakout box adapter at C2 connector.
  4. Turn ON the ignition, with the engine OFF.
  5. Use a DMM, measure voltage at C2 connector (RED) terminal 10 and terminal 20.

Is voltage within the specified value?

5 V

Go to Step 5

Go to Step 11

5

  1. Turn the ignition OFF.
  2. Using a DMM, measure resistance at C2 connector (RED) terminal 10 and terminal 20.

Is the resistance within the specified value?

3,490 ohms @ 20°C (68°F)

177.9 ohms @ 100°C (212°F)

Go to Diagnostic Aids

Go to Step 6

6

  1. Turn the ignition OFF.
  2. Disconnect the transmission 20-way connector.
  3. Using a DMM, measure resistance at the transmission side 20-way connector terminals G and H.

Is the resistance within the specified value?

3,490 ohms @ 20°C (68°F)

177.9 ohms @ 100°C (212°F)

Go to Step 8

Go to Step 7

7

  1. Remove the oil pan.
  2. Disconnect the PSM from the internal wiring harness.
  3. Using a DMM, measure pressure switch manifold (PSM) resistance at terminals E and F.

Is resistance within the specified value?

3,490 ohms @ 20°C (68°F)

177.9 ohms @ 100°C (212°F)

Go to Step 9

Go to Step 10

8

Repair the engine wiring harness. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 12

--

9

Replace the AT internal wiring harness. Refer to Wiring Harness Replacement .

Did you complete the replacement?

--

Go to Step 12

--

10

Replace the PSM. Refer to Pressure Switch Manifold Replacement .

Did you complete the replacement?

--

Go to Step 12

--

11

Important: In most cases, the TCM is not at fault. Investigate thoroughly before replacing the TCM.

Replace the TCM. Refer to Transmission Control Module Replacement .

Did you complete the replacement?

--

Go to Step 12

--

12

Perform the following procedure in order to verify the repair:

  1. Clear the DTC.
  2. Using the scan tool, monitor the TFT.
  3. Drive the vehicle under normal operating conditions. Watch for significant changes in TFT.
  4. Select Specific DTC.
  5. Enter DTC P0711.

Has the test run and passed?

 

System OK

Go to Step 1