Important: This diagnostic procedure is for manual transmission vehicles with RPO VD1 and/or RPO Z06.
The transmission fluid temperature (TFT) sensor contains a semiconductor device which changes the resistance based on the temperature, a thermistor. The TFT sensor has a signal circuit and a ground circuit. The engine control module (ECM) applies a voltage, approximately 5 volts, on the signal circuit to the sensor. The ECM monitors the changes in this voltage caused by changes in the resistance of the sensor in order to determine he fluid temperature.
When the ECM senses a signal voltage lower than the normal operating range of the sensor, DTC P0712 sets. DTC P0712 is a type C DTC.
This diagnostic procedure supports the following DTC:
DTC P0712 Transmission Fluid Temperature (TFT) Sensor Circuit Low Voltage
The engine speed is above 1,000 RPM for 7 seconds.
• | The TFT is greater than 145°C (299°F). |
• | All conditions are met for 5 seconds. |
• | The ECM does not illuminate the malfunction indicator lamp (MIL). |
• | The ECM records the operating conditions when the Conditions for Setting the DTC are met. The ECM stores this information as Failure Records. |
• | The ECM stores DTC P0712 in ECM history. |
• | A scan tool can clear the DTC. |
• | The ECM clears the DTC from ECM history if the vehicle completes 40 warm-up cycles without a non-emission-related diagnostic fault occurring. |
• | The ECM cancels the DTC default actions when the fault no longer exists and the DTC passes. |
Important:
• Remove any debris from the ECM connector surfaces before servicing the ECM. Inspect the ECM connector gaskets when diagnosing/replacing the module. Ensure that the gaskets are installed correctly. The gaskets prevent contaminate intrusion into the
ECM. • For any test that requires probing the ECM or a component harness connector, use the
J 35616
GM terminal test kit. Using this kit prevents damage to the harness/component terminals. Refer to
Using Connector Test Adapters
.
• | If the engine has sat overnight, the TFT and the intake air temperature values should display within a few degrees of each other. If the temperatures are not within 3°C (5°F), refer to Temperature Versus Resistance . |
• | For an intermittent, refer to Symptoms - Engine Controls . |
The numbers below refer to the step numbers on the diagnostic table.
This step determines if the malfunction is present.
Using the Freeze Frame/Failure Records data may aid in locating an intermittent condition. If you cannot duplicate the DTC, the information included in the Freeze Frame/Failure Records data can help determine how many miles since the DTC set. The Fail Counter and Pass Counter can also help determine how many ignition cycles the diagnostic reported a pass and/or a fail. Operate the vehicle within the same freeze frame conditions, such as RPM, load, vehicle speed, temperature, that you observed. This will isolate when the DTC failed.
A TFT below -30°C (-22°F) indicates the ECM and the TFT sensor wiring are OK.
Disconnecting the ECM enables the DMM to test continuity of the circuits. This aids in locating an open or a shorted circuit.
This step inspects for proper terminal tension/connections at the ECM harness before replacing the ECM.
Step | Action | Values | Yes | No | ||||
---|---|---|---|---|---|---|---|---|
1 | Did you perform the Diagnostic System Check - Vehicle? | -- | Go to Step 2 | |||||
Important: Record the Failure Records before clearing the DTCs. Using the Clear Info function erases the Failure Records from the ECM. Is the TFT sensor above the specified value? | 150°C (302°F) | Go to Step 4 | Go to Step 3 | |||||
Does the scan tool indicate that the diagnostic failed this ignition? | -- | Go to Step 4 | Go to Diagnostic Aids | |||||
Is the TFT sensor below the specified value? | -30°C (-22°F) | Go to Step 6 | Go to Step 5 | |||||
Did you find and correct the condition? | -- | Go to Step 8 | Go to Step 7 | |||||
6 | Replace the TFT sensor. Refer to Transmission Fluid Temperature Sensor Replacement . Is the action complete? | -- | Go to Step 8 | -- | ||||
Replace the ECM. Refer to Control Module References for replacement, setup, and programming. Is the action complete? | -- | Go to Step 8 | -- | |||||
8 | Perform the following procedure in order to verify the repair:
Has the test run and passed? | -- | Go to Step 9 | Go to Step 2 | ||||
9 | With the scan tool, observe the stored information, capture info and DTC info. Does the scan tool display any DTCs that you have not diagnosed? | -- | System OK |