DTC P0712 Transmission Fluid Temperature (TFT) Sensor Circuit Low Input 2.2L
Circuit Description
The Automatic Transmission Fluid Temperature (TFT) sensor is a thermistor within the Automatic Transmission Fluid Pressure Manual Valve Position Switch (TFP Val. Position Sw.). The TFT sensor controls the signal voltage to the PCM. The PCM supplies a 5-volt reference signal to the sensor on circuit 1227. When the transmission fluid is cold, the sensor resistance is high. The PCM detects high signal voltage. As the transmission fluid temperature increases to a normal operating temperature, the sensor resistance becomes less and the voltage decreases.
When the PCM detects a continuous short to ground in the TFT signal circuit or in the TFT sensor, then DTC P0712 sets. DTC P0712 is a type D DTC.
Conditions for Setting the DTC
| • | The system voltage is 10-16 volts. |
| • | The ignition switch is in the RUN position. |
| • | The TFT is equal to or greater than 151°C (304°F). |
| • | All conditions met for 10 seconds. |
Action Taken When the DTC Sets
| • | The PCM determines a default Transmission Fluid Temperature (TFT) using the following matrix: |
| Important: The actions listed below are in order of highest to lowest priority. |
| 1. | If any Engine Coolant Temperature (ECT) DTCs P0117, P0118, P1114 or P1115 are set, then the default TFT is equal to 135°C (275°F). |
| 2. | If the ECT is 125°C (257°F) or more, then the default TFT is equal to 135°C (275°F). |
| 3. | If the Engine Run Time is less than 300 seconds and: |
| • | No Intake Air Temperature (IAT) DTCs P0112 or P0113 are set and IAT is available, then the default TFT is equal to IAT. |
| • | Any Intake Air Temperature (IAT) DTCs P0112 or P0113 are set or IAT is NOT available, then the default TFT is equal to 90°C (194°F). |
| 4. | If the Engine Run Time is greater than 300 seconds and No Intake Air Temperature (IAT) DTCs P0112 or P0113 are set and IAT is available and Engine Coolant Temperature (ECT) is between 40 and 125°C (104 and 257°F) and: |
| • | IAT at startup is less than 15°C (59°F), then the default TFT is equal to the Engine Coolant Temperature (ECT) plus 5°C (8°F). |
| • | IAT at startup is greater than 35°C (95°F), then the default TFT is equal to the Engine Coolant Temperature (ECT) plus 10°C (16°F). |
| • | IAT at startup is between 15 and 35°C (59 and 95°F), then the default TFT is equal to the Engine Coolant Temperature (ECT). |
| 5. | If the Engine Run Time is greater than 300 seconds and any Intake Air Temperature (IAT) DTCs P0112 or P0113 are set or IAT is NOT available, then the default TFT is equal to the Engine Coolant Temperature (ECT). |
| 6. | If the Engine Run Time is greater than 300 seconds and ECT is less than 40°C (104°F) or more, then the default TFT is equal to 60°C (140°F). |
| • | The PCM freezes shift adapts from being updated. |
| • | The PCM does not illuminate the Malfunction Indicator Lamp (MIL). |
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. |
| • | Use the Temperature vs Resistance scale when testing the TFT sensor at various temperature levels. Test the TFT sensor in order to evaluate the possibility of a skewed (mis-scaled) sensor. A skewed sensor can result in delayed garage shifts or TCC complaints. |
| • | The scan tool displays the transmission fluid temperature in degrees. After the transmission is operating, the fluid temperature should rise steadily to a normal operating temperature, then stabilize. |
| • | Verify customer driving habits, trailer towing, etc. |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
This step tests for a short to ground or a skewed sensor.
-
This step creates an open within the transmission in order to test for an internal fault.
Step | Action | Value(s) | Yes | No | ||||
|---|---|---|---|---|---|---|---|---|
1 | Was the Powertrain On-Board Diagnostic (OBD) System Check performed? | -- | Go to OBD System Check | |||||
2 | Perform the transmission fluid checking procedure. Refer to 4L60-E Transmission Fluid Checking Procedure. Have you performed the fluid checking procedure? | -- | Go to 4L60-E Transmission Fluid Checking Procedure | |||||
Important: Before clearing the DTCs, use the scan tool in order to record the Freeze Frame and Failure Records for reference. The Clear Info function will erase the data. Does the scan tool display a TFT sensor signal voltage less than the specified value? | 0.2 volts | Go to Diagnostic Aids | ||||||
Does the scan tool display a TFT sensor signal voltage greater than the specified value? | 4.92 volts | |||||||
5 |
Is the resistance within specifications? | 3088-3942 ohms at 20°C (68°F) 159-198 ohms at 100°C (212°F) | Go to Diagnostic Aids | |||||
6 | Inspect the Automatic Transmission Wiring Harness Assembly for a short to ground. Refer to Electrical Diagnosis, Section 8A. Did you find a problem? | -- | ||||||
7 |
Is the resistance within specifications? | 3088-3942 ohms at 20°C (68°F) 159-198 ohms at 100°C (212°F) | Go to Diagnostic Aids | |||||
8 | Replace the TFT Sensor (this is part of the TFP Val. Position Sw.). Refer to Automatic Transmission Fluid Pressure Manual Valve Position Switch/4L60-E Automatic Transmission On-Vehicle Service. Is the replacement complete? | -- | -- | |||||
9 | Inspect circuit 1227 for a short to ground. Refer to Electrical Diagnosis, Section 8A. Did you find a problem? | -- | ||||||
10 | Replace the PCM. Refer to PCM Replacement, Section 6. Is the replacement complete? | -- | -- | |||||
11 | In order to verify your repair, perform the following procedure:
Has the test run and passed? | -- | System OK |
DTC P0712 Transmission Fluid Temperature (TFT) Sensor Circuit Low Input 4.3L
Circuit Description
The Automatic Transmission Fluid Temperature (TFT) sensor is a thermistor within the Automatic Transmission Fluid Pressure Manual Valve Position Switch (TFP Val. Position Sw.). The TFT sensor controls the signal voltage to the 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 a normal operating temperature, the sensor resistance becomes less and the signal voltage decreases.
When the VCM detects a continuous short to ground in the TFT signal circuit or in the TFT sensor, then DTC P0712 sets. DTC P0712 is a type B DTC.
Conditions for Setting the DTC
DTC P0712 sets if the following conditions occur two consecutive times:
| • | The system voltage is 10-19 volts. |
| • | The ignition switch is in the RUN position. |
| • | The TFT sensor indicates a voltage less than 0.2 volts. |
| • | All conditions met for 10 seconds. |
Action Taken When the DTC Sets
| • | The VCM uses a transmission fluid temperature default value of 135°C (275°F). |
| • | The VCM freezes shift adapts from being updated. |
| • | The VCM illuminates the Malfunction Indicator Lamp (MIL). |
Conditions for Clearing the MIL/DTC
| • | 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 is OFF long enough in order to power down the VCM. |
Diagnostic Aids
| • | 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. |
| • | Use the Temperature vs Resistance scale when testing the TFT sensor at various temperature levels. Test the TFT sensor in order to evaluate the possibility of a skewed (mis-scaled) sensor. A skewed sensor can result in delayed garage shifts or TCC complaints. |
| • | The scan tool displays the transmission fluid temperature in degrees. After the transmission is operating, the fluid temperature should rise steadily to a normal operating temperature, then stabilize. |
| • | Verify the customer's driving habits, trailer towing, etc. |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
This step tests for a short to ground or a skewed sensor.
-
This step creates an open within the transmission in order to test for an internal fault.
Step | Action | Value(s) | Yes | No | ||||
|---|---|---|---|---|---|---|---|---|
1 | Was the Powertrain On-Board Diagnostic (OBD) System Check performed? | -- | Go to Powertrain OBD System Check | |||||
2 | Perform the transmission fluid checking procedure. Refer to 4L60-E Transmission Fluid Checking Procedure. Was the fluid checking procedure performed? | -- | Go to 4L60-E Transmission Fluid Checking Procedure | |||||
Important: Before clearing the DTCs, use the scan tool in order to record the Freeze Frame and Failure Records for reference. The Clear Info function will erase the data. Does the scan tool display a TFT sensor signal voltage less than the specified value? | 0.2 volts | Go to Diagnostic Aids | ||||||
Does the scan tool display a TFT sensor signal voltage greater than the specified value? | 4.92 volts | |||||||
5 |
Is the resistance within specifications? | 3088-3942 ohms at 20°C (68°F) 159-198 ohms at 100°C (212°F) | Go to Diagnostic Aids | |||||
6 | Inspect the Automatic Transmission Wiring Harness Assembly for a short to ground. Refer to Electrical Diagnosis, Section 8A. Did you find a problem? | -- | ||||||
7 |
Is the resistance within specifications? | 3088-3942 ohms at 20°C (68°F) 159-198 ohms at 100°C (212°F) | Go to Diagnostic Aids | |||||
8 | Replace the TFT Sensor (this is part of the TFP Val. Position Sw.). Refer to Automatic Transmission Fluid Pressure Manual Valve Position Switch Replacement/4L60-E Automatic Transmission On-Vehicle Service. Is the replacement complete? | -- | -- | |||||
9 | Inspect circuit 1227 for a short to ground. Refer to Electrical Diagnosis, Section 8A. Did you find a problem? | -- | ||||||
10 | Replace the VCM. Refer to VCM Replacement, Section 6. Is the replacement complete? | -- | -- | |||||
11 | In order to verify your repair, perform the following procedure:
Has the test run and passed? | -- | System OK |
