GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The Transmission Fluid Temperature (TFT) sensor is located by the control valve body of the transmission.

When the transmission fluid is cold, the sensor resistance is high. As the transmission fluid warms up, the sensor resistance decreases. The PCM monitors the TFT circuit.

When the PCM detects a continuous short to ground in the TFT circuit, then DTC P0712 sets.

DTC P0712 is a type A DTC.

Conditions for Running the DTC

PCM detects a short to ground in the TFT circuit 4 times (2 trip detection logic).

Conditions for Setting the DTC

DTC P0712 sets when the following condition occurs:

The PCM detects a short to ground in the TFT sensor circuit.

Action Taken When the DTC Sets

    • At the time of the failure, the PCM records the operating conditions when the Conditions for Setting the DTC are met. The PCM stores this information as a Failure Record.
    • The PCM illuminates the malfunction indicator lamp (MIL) during the second consecutive drive trip in which the Conditions for Setting the DTC are met.
    • The PCM stores DTC P0712 in PCM history.

Conditions for Clearing the MIL/DTC

    • A scan tool can clear the MIL/DTC.
    • The PCM clears the DTC from PCM history if the vehicle completes 40 warm-up cycles without an emission related diagnostic fault occurring.

Test Description

The number below refers to the step number on the diagnostic table.

  1. This step tests for a short to ground condition in the wiring harness.

DTC P0712

Step

Action

Value(s)

Yes

No

Schematic Reference: Automatic Transmission Controls Schematics

1

Did you perform the Diagnostic System Check - Engine Controls - 1.8L (LV6)?

--

Go to Step 2

Go to Diagnostic System Check - Engine Controls in Engine Controls - 1.8L (LV6).

2

  1. Install a 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 PCM Freeze Frame Failure Records. Using the Clear Info function erases the Freeze Frame Failure Records from the PCM.
       • Using the Clear Info function erases stored DTCs in the PCM.

  4. Record the DTC Freeze Frame and Failure Records.
  5. Clear the DTC.

Is the action complete?

--

Go to Step 3

--

3

  1. Turn OFF the ignition.
  2. Disconnect the PCM.
  3. Test the circuit from the PCM to the TFT sensor for a short to ground. Refer to Testing for Short to Ground in Wiring Systems.

Did you find a condition?

--

Go to Step 6

Go to Step 4

4

  1. Remove the transmission oil pan.
  2. Test the TFT sensor wiring from the 10-way connector to the TFT sensor connector for the following conditions:
  3. • Short to ground.
    • Refer to Testing for Short to Ground in Wiring Systems.

Did you find a condition?

--

Go to Step 7

Go to Step 8

5

Replace the PCM. Refer to Powertrain Control Module Replacement in Engine Controls - 1.8L (LV6).

Is the action complete?

--

Go to Step 9

--

6

Perform the necessary wiring repairs. Refer to Wiring Repairs in Wiring Systems.

Is the action complete?

--

Go to Step 9

--

7

Replace the internal transmission wiring harness. Refer to Solenoids and Wiring Harness Replacement .

Is the action complete?

--

Go to Step 9

--

8

Replace the TFT sensor. Refer to Solenoids and Wiring Harness Replacement .

Is the action complete?

--

Go to Step 9

--

9

Perform the following procedure in order to verify the repair:

  1. Select DTC.
  2. Select Clear Info.
  3. Turn ON the ignition, with the engine OFF.
  4. Select Specific DTC.
  5. Enter DTC P0712.

Has the test run and passed?

--

Go to Step 10

Go to Step 2

10

With the scan tool, observe the stored information, capture info and DTC info.

Does the scan tool display any DTCs that you have not diagnosed?

--

Go to Diagnostic Trouble Code (DTC) List in Engine Controls - 1.8L (LV6)

System OK