P0712

DTC P0712 Fluid Temperature Sensor CKT Low Input (Gas [1 Of 2]):

DTC P0712 Fluid Temperature Sensor CKT Low Input (Gas [2 Of 2]):

Fluid Temperature Sensor Circuit (Gas):

CIRCUIT DESCRIPTION
The Transmission Fluid Temperature (TFT) is a thermistor that controls the signal voltage to the Vehicle Control Module (VCM). The VCM supplies a 5 volt reference signal to the sensor on circuit 1227. When the transmission fluid is cold, the sensor resistance is high. The VCM detects high signal voltage. As the transmission fluid temperature increases to normal operating temperature, the sensor resistance becomes less, and the voltage decreases to 1.5-2 volts.

When the VCM detects a continuous short to ground in the TFT Sensor or signal circuit, then DTC P0712 sets. DTC P0712 is a type D DTC. For California emission vehicles, DTC P0712 is a type B DTC.

CONDITIONS FOR SETTING THE DTC

^ The ignition is ON.
^ The TFT Sensor indicates a voltage of less than 0.2 volts.
^ All conditions met for 10 seconds.

ACTION TAKEN WHEN THE DTC SETS

^ The transmission default temperature is 140°C (275°F). The scan tool does not display the default temperature.
^ VCM freezes shift adapts from being updated.
^ For California Emissions only, the VCM illuminates the Malfunction Indicator Lamp (MIL).

CONDITIONS FOR CLEARING THE MIL/DTC

^ For California Emissions only, the VCM turns off the MIL after three consecutive ignition cycles without a failure reported.
^ A scan tool can clear the DTC from the VCM history. The VCM clears the DTC from the VCM history if the vehicle completes 40 warm-up cycles without a failure reported.
^ The VCM cancels the DTC default actions when the fault no longer exists and the ignition cycles OFF long enough to power down the VCM.

DIAGNOSTIC AIDS

^ With a transmission fluid over temperature DTC P1812 also set, inspect the transmission cooling system.
^ Inspect the harness routing for a potential short to ground in circuit 1227.
^ Inspect the wiring for poor electrical connections at the VCM. 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 the TFT Sensor at various temperatures in order to evaluate the possibility of a "skewed" (mis-scaled) sensor. Use the temperature to resistance value scale. A "skewed" sensor may cause delayed garage shifts or Torque Converter Clutch (TCC) complaints.
^ Verify the customer driving habits, trailer towing, weight, or towing in Overdrive.
^ First diagnose and clear any engine DTCs or Throttle Position (TP) Sensor codes that are present. Then inspect for any transmission DTCs that may have reset.

TEST DESCRIPTION
The numbers below refer to the step numbers on the diagnostic chart.

3. Step 3 tests for a short to ground or a "skewed" sensor by verifying the fault still exists.
4. Step 4 tests for an internal fault within the transmission by creating an open.