P0712

P0712 WITH 4 SPEED AUTOMATIC

Diagnostic Chart:

Wiring Diagram:

CIRCUIT DESCRIPTION

The Automatic Transmission Fluid Temperature (TFT) sensor is a thermistor. The TFT sensor is part of the Automatic Transmission Fluid Pressure Manual Valve Position Switch (TFP Val. Position Sw.). The Powertrain Control Module (PCM) supplies a 5-volt reference signal to the sensor on circuit 1227. When the transmission fluid is cold, the sensor resistance is high and the PCM senses a high signal voltage. As the transmission fluid warms, the sensor resistance lowers and the PCM senses lower voltage. The PCM uses the TFT reading in order to control the Torque Converter Clutch (TCC), line pressure adjustments, and temperature compensated shifts.

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

CONDITIONS FOR SETTING THE DTC

^ The ignition switch is RUN position.

^ The TFT voltage is less than 0.33 volts for 10 seconds.

ACTION TAKEN WHEN THE DTC SETS

^ The PCM does not illuminate the Malfunction Indicator Lamp (MIL).

^ DTC P0712 is stored in the PCM history.

^ The PCM freezes shift adapts from being updated.

^ The PCM calculates transmission temperature based on engine coolant temperature, intake manifold air temperature, and engine run time.

CONDITIONS FOR CLEARING THE DTC

^ 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.

DIAGNOSTIC AIDS

^ Inspect the wiring for poor electrical connections at the PCM. Inspect the wiring for poor electrical connections at the transmission 20-way connector. Look 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 condition massage the wiring harness while watching the test equipment for a change.

TEST DESCRIPTION

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

3. This Step tests the PCM's ability to detect an open circuit.

5. This Step tests the TFT sensor for correct resistance.