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For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 2002 🢒 DeVille 🢒 Transmission/Transaxle 🢒 Automatic Transaxle - 4T80-E 🢒 DTC P0712

Object Number: 654442 Size: SF
Master Electrical Component List
Automatic Transmission Controls Schematics
OBD II Symbol Description Notice

Circuit Description

The automatic transmission fluid temperature (TFT) sensor is a negative coefficient thermistor whose resistance value changes based on temperature. The PCM provides a 5 volt reference to the sensor. A high fluid temperature or a short to ground on the signal circuit results in low signal voltage. The TFT operating range is -40 to +151°C (-40 to +305°F).

If the PCM detects a continuous short to ground in the TFT sensor circuit, then DTC P0712 sets. DTC P0712 is a type C DTC.

Conditions for Running the DTC
    • The system voltage is 8-18 volts.
    • The engine run time is greater than 5 seconds.

Conditions for Setting the DTC

The PCM detects a TFT of 149°C (300°F) or greater for 10 seconds.

Action Taken When the DTC Sets
    • The PCM does not illuminate the malfunction indicator lamp (MIL).
    • The PCM calculates a default transmission fluid temperature based on engine coolant temperature, intake air temperature and engine run time.
    • The PCM records the operating conditions when the Conditions for Setting the DTC are met. The PCM stores this information as Failure Records.
    • The PCM stores DTC P0712 in PCM history.

Conditions for Clearing the DTC
    • A scan tool can clear the DTC.
    • The PCM clears the DTC from PCM history if the vehicle completes 40 warm-up cycles without a non-emission related diagnostic fault occurring.
    • The PCM cancels the DTC default actions when the fault no longer exists and the DTC passes.

Test Description

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

  1. This step verifies DTC P0712 by indicating a short to ground. If the scan tool does not display a transmission fluid temperature equal to or greater than 149°C (300°F), then the DTC is intermittent.

    2.

  2. This step isolates the transmission. If the scan tool displays a transmission fluid temperature less than -38°C (-36°F), then the engine wiring harness is good.

DTC P0712

Step

Action

Value(s)

Yes

No

1

Did you perform the Powertrain Diagnostic System Check?

--

Go to Step 2

Go to Diagnostic System Check - Engine Controls in Engine Controls

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 Failure Records. Using the Clear Info function erases the Failure Records from the PCM.

  3. Record the DTC Failure Records.
  4. Clear the DTC.
  5. Select Trans. Fluid Temp. on scan tool.

Does the scan tool display a Trans. Fluid Temp. less than the specified value?

149°C (300°F)

Go to Intermittent Conditions in Engine Controls

Go to Step 3

3

  1. Turn OFF the ignition.
  2. Disconnect the AT inline 20-way connector. Additional DTCs may set.
  3. Turn ON the ignition, with the engine OFF.

Does the scan tool display a Trans. Fluid Temp. less than the specified value?

-38°C (-36°F)

Go to Step 5

Go to Step 4

4

Test the signal circuit (CKT 1227) of the TFT sensor for a short to ground between the PCM connector C2 and the AT inline 20-way connector.

Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 11

Go to Step 10

5
  1. Install the J 44152 Jumper Harness (20 pins) on the transmission side of the AT inline 20-way connector.
  2. Using the DMM and the J 35616 GM Terminal Test Kit, measure the resistance between terminals L and M of the J 44152 .

    3. Refer to Automatic Transmission Inline Harness Connector End View .

Is the resistance within the range specified for the given transmission temperatures?

20°C (68°F)

3088-3,942 ohms

80°C (176°F)

159-198 ohms

Go to Step 6

Go to Step 7

6

Measure the resistance between terminal L of the J 44152 and ground.

Refer to Automatic Transmission Inline Harness Connector End View .

Is the resistance less than the specified value?

100 ohms

Go to Step 9

Go to Intermittent Conditions in Engine Controls

7
  1. Disconnect the TFT sensor from the automatic transmission wiring harness.
  2. Measure the resistance between terminal L and all other terminals of the J 44152 .

    3. Refer to Automatic Transmission Inline Harness Connector End View .

Is the resistance between terminal L and any other terminal less than the specified value?

100 ohms

Go to Step 9

Go to Step 8

8

Replace the TFT sensor.

Refer to Transmission Overhaul in the 4T80-E section of the Transmission Unit Repair Manual.

Did you complete the replacement?

--

Go to Step 11

--

9

Important: The automatic transmission wiring harness consists of two separate harnesses, the Automatic Transmission Wiring Harness Assembly, GM P/N 15320475, and the Automatic Transmission Wiring Extension Harness Assembly, GM P/N 15320478. In order to avoid the unnecessary replacement of parts, only replace the Automatic Transmission Wiring Harness Assembly, GM P/N 15320475.

Replace the automatic transmission wiring harness.

Refer to Transmission Overhaul in the 4T80-E section of the Transmission Unit Repair Manual.

Did you complete the replacement?

--

Go to Step 11

--

10

Replace the PCM.

Refer to Powertrain Control Module Replacement in Engine Controls.

Did you complete the replacement?

--

Go to Step 11

--

11

Perform the following procedure in order to verify the repair:

  1. Select DTC.
  2. Select Clear Info.
  3. Operate the vehicle under the following conditions:
    4. • Turn ON the ignition, with the engine OFF.
    • The Trans. Fluid Temp. must be 144°C (291°F) or less for 2 seconds.
  4. Select Specific DTC.
  5. Enter DTC P0712.

Has the test run and passed?

--

System OK

Go to Step 1