Diagnostic Instructions
| • | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
| • | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
| • | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
DTC Descriptors
DTC P0712: Transmission Fluid Temperature (TFT) Sensor Circuit Low VoltageDTC P0713: Transmission Fluid Temperature (TFT) Sensor Circuit High Voltage
Diagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
TFT Sensor Signal | P0712 | P0713 | P0713 | P0218, P0711 |
Low Reference | -- | P0713 | -- | P0218, P0711 |
Typical Scan Tool Data
Circuit | Short to Ground | Open/High Resistance | Short to Voltage |
|---|---|---|---|
Operating Conditions: Engine running in PARK, normal operating temperature Parameter Normal Range: -39 to +149°C (-38 to +300°F) | |||
Trans. Fluid Temp. | Greater than 149°C (300°F) | Less than -39°C (-38°F) | Less than -39°C (-38°F) |
Circuit/System Description
The automatic transmission fluid temperature (TFT) sensor is a thermistor type sensor. The transmission control module (TCM) supplies a 5-volt reference signal to the sensor. When the transmission fluid is cold, the sensor resistance is high and the TCM senses a high signal voltage. As the transmission fluid warms, the sensor resistance lowers and the TCM senses lower voltage. The TCM uses the TFT reading in order to control the torque converter clutch (TCC), line pressure adjustments, and temperature compensated shifts.
Conditions for Running the DTC
P0712
| • | The ignition voltage is between 8-18 volts. |
| • | The engine speed is between 500-6,500 RPMs for 5 seconds. |
P0713
| • | DTCs P0716, P0717, P0722 or P0723. |
| • | The ignition voltage is between 8-18 volts. |
| • | The engine speed is between 500-6,500 RPMs for 5 seconds. |
| • | The transmission output shaft speed is 64 RPM or greater for 200 seconds cumulatively. |
| • | The TCC slip speed is 120 RPM or greater for 200 seconds cumulatively. |
Conditions for Setting the DTC
P0712
The TFT sensor is greater than 150°C (302°F) for 12 seconds.
P0713
The TFT is less than -40°C (-40°F) for 80 seconds.
Action Taken When the DTC Sets
DTC P0712 and P0713 are Type C DTCs.
Conditions for Clearing the DTC
DTC P0712 and P0713 are Type C DTCs.
Reference Information
Schematic Reference
Automatic Transmission Controls Schematics
Connector End View Reference
Description and operation
Transmission General Description
Electrical Information Reference
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Special Tools
| • | J 35616 GM-Approved Terminal Test Kit |
| • | J 44152 Jumper Harness (20 Pins) |
Circuit/System Verification
- Start the engine.
- The vehicle in PARK and at normal operating temperature, observe the transmission fluid temperature parameter on the scan tool. The transmission fluid temperature should display a temperature near the ECT sensor parameter.
Circuit/System Testing
- Ignition OFF, disconnect the transmission 20-way harness connector.
- Ignition OFF, test the TCM side of the transmission 20-way harness connector for less than 5 ohms between the low reference circuit terminal M and ground.
- Ignition ON, verify that the TFT sensor parameter is at -40°C (-40°F).
- Install a 3-amp fused jumper wire between the signal circuit terminal L and the low reference circuit terminal M on the TCM side of the transmission 20-way harness connector. Verify the TFT sensor parameter is greater than 128°C (262°F).
- If all circuits test normal, test or replace the internal transmission wiring harness or the TFT sensor.
| ⇒ | If greater than the specified range, test the low reference circuit for a an open/high resistance. If the circuit tests normal, replace the TCM. |
| ⇒ | If greater than the specified range, test the TCM side of the 20-way harness connector signal circuit terminal L for a short to ground. If the circuit tests normal, replace the TCM. |
Important: If the signal circuit of the TFT sensor is shorted to voltage the TFT sensor may be damaged.
| ⇒ | If less than the specified range test the signal circuit of the TFT sensor for a short to voltage or an open/high resistance. If the circuit tests normal, replace the TCM. |
Component Testing
Install the J 44152 on the transmission side of the AT 20-way inline connector. Using the J 35616 measure the resistance between the TFT sensor signal circuit and the low reference circuit. Refer to Transmission Fluid Temperature Sensor Specifications.
| ⇒ | If the resistance is not within the specified range, replace the transmission wiring harness or the TFT sensor. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the repair.
| • | Control Module References for TCM replacement, setup, and programming |
