GM Service Manual Online
For 1990-2009 cars only

DTC Description

This diagnostic procedure covers the following DTCs:

    • DTC P0218--Transmission Fluid Over-temperature
    • DTC P0711--Transmission Fluid Temperature Sensor Circuit Range/Performance
    • DTC P0712--Transmission Fluid Temperature Sensor Circuit Low Input
    • DTC P0713--Transmission Fluid Temperature Sensor Circuit High Input

Circuit Description

The PCM applies a reference 5 volts to the transmission fluid temperature (TFT) sensor signal circuit 1227 and ground through ground circuit 2762. The TFT sensor is a variable resistor that measures the temperature of the transmission fluid.

    • Increased transmission fluid temperature results in the following:
       - The TFT sensor resistance decreases
       - Increased TFT sensor signal circuit pull-down rate to ground
       - The TFT sensor signal voltage is decreased
    • Decreased transmission fluid temperature results in the following:
       - The TFT sensor resistance increases
       - Decreased TFT sensor signal circuit pull-down rate to ground
       - The TFT sensor signal voltage is increased

A transmission fluid over-temperature DTC sets if the PCM detects that the transmission fluid temperature is outside the predetermined range.

Conditions for Running the DTC

P0218

    • No TFT sensor DTCs are set.
    • The ignition is ON for greater than 5 seconds.

P0711

    • No VSS or transmission component slipping DTCs are set.
    • The system voltage is between 8.0-18.0 volts.
    • The engine is running for greater than 409 seconds.
    • The vehicle speed is greater than 8 km/h for 409 seconds cumulative during the current ignition cycle.
    • The TCC slip speed is greater than 120 RPM for 409 seconds cumulative during the current ignition cycle.
    • The TFT at start-up is between -40 and +21°C.
    • The engine coolant temperature (ECT) is greater than 70°C and has changed by 50°C since start-up.

P0712 and P0713

    • The system voltage is between 8.0-18.0 volts.
    • The ignition is ON.

Conditions for Setting the DTC

P0218

The TFT is greater than 130°C for 10 minutes.

P0711

    • The TFT does not change more than 1.5°C for 409 seconds since start-up.
        OR
    • The TFT changes more than 20°C in 200 milliseconds, 14 times within 7 seconds.

P0712

The TFT sensor indicates a signal voltage less than 0.2 volt for 10 seconds.

P0713

The TFT sensor indicates a signal voltage greater than 4.92 volts for 10 seconds.

Conditions for Clearing the DTC

    • DTC P0218 is a Type B DTC. Refer to Electronic Component Description for Action Taken when Type B DTCs set and Conditions for Clearing Type B DTCs.
    • DTCs P0711, P0712 and P0713, are Type C DTCs. Refer to Electronic Component Description for Action Taken when Type C DTCs set and Conditions for Clearing Type C DTCs.

Additional Information

    • Refer to Transmission Fluid Temperature Sensor Specifications for details of the TFT sensor operation.
    • For an intermittent fault condition, refer to Intermittent Conditions.
    • The Transmission Fluid Temperature Sensor Circuit Diagnostic table is developed with the assumption that the transmission cooling system and mechanical integrity is serviceable. Rectify any transmission cooling system or mechanical fault conditions before proceeding with this diagnostic table.
    • Since a fault condition in a wiring connector may trigger DTCs, always test the connectors related to this diagnostic procedure for shorted terminals or poor wiring connection before replacing any component. Refer to Automatic Transmission Controls Schematics for information on electrical fault diagnosis.
    • Refer to Automatic Transmission Controls Schematics , Automatic Transmission Inline 20-Way Connector End View , Automatic Transmission Internal Connector End Views , Automatic Transmission Control Module Connector End Views , and Automatic Transmission Related Connector End Views to aid in the diagnosis procedures.

Test Description

The following number refers to the step number in the diagnostic chart.

8 This diagnostic table only tests the TFT circuits outside the transmission. Check for damaged wiring or poor connections inside the transmission assembly before replacing the TFT sensor.

Step

Action

Value(s)

Yes

No

1

Was the Main Diagnostic Table performed?

--

Go to Step 2

Refer to Diagnostic System Check - Automatic Transmission

2

  1. Test the transmission assembly for correct operation. Refer to Diagnostic Starting Point - Automatic Transmission. In particular, check for the following conditions:
  2. • Transmission fluid level
    • Transmission fluid cooling system restrictions/blockages
    • Air flow restrictions/blockage
    • Debris in the transmission fluid
    • Incorrect line pressure
    • Torque converter stator operation
    • Transmission overloading
  3. Test the engine cooling system for correct operation. Refer to Diagnostic Starting Point - Engine Cooling.

Was any fault found and rectified?

--

Go to Step 10

Go to Step 3

3

  1. Observe the Freeze Frame/Failure Record for this DTC.
  2. Switch OFF the ignition for 30 seconds.
  3. Operate the vehicle within the Conditions for Running the DTC or within the conditions in the Freeze Frame/Failure Records.
  4. Using Tech 2, select Engine/Diagnostic Trouble Codes/Read DTC Information.

Does DTC P0218, P0711, P0712, or P0713 fail this ignition cycle?

--

Go to Step 4

Refer to Diagnostic Aids for the Transmission Fluid Temperature Sensor Circuit DTCs

4

  1. Switch OFF the ignition.
  2. Disconnect connector X121-X2 from the transmission.
  3. Switch ON the ignition with the engine not running.
  4. Using a digital multimeter, measure the voltage between the TFT sensor signal circuit and the PCM housing.

Is the voltage within the specified range?

4.8-5.2 V

Go to Step 5

Go to Step 6

5

  1. Switch OFF the ignition.
  2. Remove the PCM fuse 29 from the engine compartment fuse and relay panel assembly.
  3. Important: Install the PCM fuse 29 to the engine compartment fuse and relay panel assembly after completing the test.

  4. Using a digital multimeter, measure the resistance between the TFT sensor low reference circuit and the PCM housing.

Is the resistance less than the specified value?

Go to Step 8

Go to Step 7

6

Test the TFT sensor signal circuit for a high resistance, open circuit, short to ground, or short to voltage fault condition. Refer to Automatic Transmission Controls Schematics for information on electrical fault diagnosis.

Was any fault found and rectified?

--

Go to Step 10

Go to Step 9

7

Test the TFT sensor low reference circuit for a high resistance, open circuit, short to ground, or short to voltage fault condition. Refer to Automatic Transmission Controls Schematics for information on electrical fault diagnosis.

Was any fault found and rectified?

--

Go to Step 10

Go to Step 9

8

Important: Check for damaged wiring (short to ground, short to voltage, high resistance, or open circuit) or poor connections inside the transmission assembly before replacing the TFT sensor.

Replace the TFT sensor. Refer to Transmission Fluid Temperature Sensor Specifications.

Was the repair completed?

--

Go to Step 10

--

9

Replace the PCM. Refer to Powertrain Control Module Replacement.

Was the repair completed?

--

Go to Step 10

--

10

  1. Using Tech 2, clear the DTCs.
  2. Switch OFF the ignition for 30 seconds.
  3. Start the engine.
  4. Operate the vehicle within the Conditions for Running the DTC or within the conditions in the Freeze Frame/Failure Records.

Do any TFT sensor circuit DTCs fail this ignition cycle?

--

Go to Step 2

Go to Step 11

11

Using Tech 2, select the DTC Display function.

Are there any DTCs displayed?

--

Go to the appropriate DTC Table

System OK

When all diagnosis and repairs are completed, check the powertrain management system for correct operation.