Circuit Description
The Automatic Transmission Fluid Temperature (TFT) sensor is a negative coefficient thermistor. When the transmission fluid is cold, the sensor resistance is high. As the transmission fluid warms, the sensor resistance decreases. The TFT range is -40 to +150°C (-40 to +302°F).
The PCM provides a 5 volt reference through a fixed series resistor, to the TFT circuit and monitors the voltage after the resistor, as the voltage drop (signal) across the circuit.
When the PCM detects a voltage input greater than 4.92 volts in the TFT Sensor circuit, indicating an open or short to power, then DTC P0713 sets. DTC P0713 is a type D DTC.
Conditions for Setting the DTC
| • | System voltage is 10-16 volts. |
| • | The ignition is ON. |
| • | The PCM detects a transmission fluid temperature of -35°C (-31°F) or less (4.92 volts or more) for 7 minutes. |
Action Taken When the DTC Sets
| • | The PCM does not illuminate the Malfunction Indicator Lamp (MIL). |
| • | The PCM calculates a transmission fluid default temperature as follows: |
| • | If the Engine Run Time is less than 3 minutes and: |
| - | The Intake Air Temperature (IAT) DTC(s) P0112, P0113, P1111 or P1112 is set, then the default Automatic Transmission Fluid Temperature (TFT) is set to 0°C (32°F). |
| - | No IAT DTC is set, then the default TFT is set to the IAT saved at start up. |
| • | If the engine run time is greater than 3 minutes and: |
| - | The Engine Coolant Temperature (ECT) DTC(s) P0117, P0118, P1114 or P1115 is set, then the default TFT is set to 131°C (268°F). |
| - | No ECT DTC is set, and: |
| • | The ECT is less than 45°C (113°F), then the default TFT is set to 12°C (54°F). |
| • | The ECT is greater than 115°C (239°F), then the default TFT is set to 131°C (268°F). |
| - | No ECT DTC is set, the ECT is 45-115°C (113-239°F) and: |
| • | The IAT DTC(s) P0112, P0113, P1111 or P1112 is set, then the default TFT is set to equal the ECT. |
| • | The IAT at start up is less than 0°C (32°F), then the default TFT is set to the ECT value minus 10°C (18°F). |
| • | The IAT at start up is greater than 28°C (82°F), then the default TFT is set to the ECT value plus 10°C (18°F). |
| • | The IAT at start up is 0-28°C (32-82°F), then the default TFT is set equal to the ECT value. |
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 at the PCM, the transmission connector and all other circuit connecting points 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 |
| - | Moisture intrusion |
| - | Corrosion |
| • | When diagnosing for an intermittent short or open, massage the wiring harness while watching the test equipment for a change. |
| • | Test the TFT Sensor at various temperature levels in order to evaluate the possibility of a skewed (mis-scaled) sensor. |
| Refer to Temperature vs Resistance . |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
A Scan Tool display greater than 4.9 volts indicates this DTC is current.
-
This step isolates the fault between the transmission harness or the engine harness.
Step | Action | Value(s) | Yes | No | ||||
|---|---|---|---|---|---|---|---|---|
1 | Was the Powertrain On-Board Diagnostic (OBD) System Check performed? | -- | Go to Powertrain On Board Diagnostic (OBD) System Check in Engine Controls | |||||
2 | Perform the Transmission Fluid Checking Procedure. Refer to Transmission Fluid Check . Have you performed the procedure? | -- | Go to Transmission Fluid Check | |||||
Important: Before clearing the DTCs, use the Scan Tool in order to record the Failure Records for reference. The Clear Info function will erase the stored Failure Records from the PCM. Does the Scan Tool display an Automatic Transmission Fluid Temperature (TFT) less than the specified value? | -36°C (-33°F) | Go to Diagnostic Aids | ||||||
Important: If the ignition is in the RUN position for more than 5 minutes, the PCM uses the default transmission temperature. Does the Scan Tool display a TFT greater than the specified value? | 145°C (293°F) | |||||||
5 | Connect circuit 1227, terminal F to a known good ground. Does the Scan Tool display a TFT greater than the specified value? | 145°C (293°F) | ||||||
6 | Inspect circuit 1227 of the engine harness for an open. Refer to General Electrical Diagnosis Procedures in Wiring Systems. Was a condition found and corrected? | -- | ||||||
7 | Inspect circuit 1057 of the engine harness for an open. Refer to General Electrical Diagnosis Procedures in Wiring Systems. Was a condition found and corrected? | -- | ||||||
8 | Inspect transmission circuits 1227 and 452 for an open. Refer to General Electrical Diagnosis Procedures in Wiring Systems. Was a condition found? | -- | ||||||
9 | Replace the Automatic Transmission Wiring Harness. Refer to Solenoids and Wiring Harness Replacement . Is the replacement complete? | -- | -- | |||||
10 | Replace the TFT Sensor. Refer to Fluid Temperature Sensor Replacement . Is the replacement complete? | -- | -- | |||||
11 | Inspect PCM connector C2 (Clear) for bent, damaged or backed out connector pins. Was a condition found and corrected? | -- | ||||||
12 | Replace the PCM. Refer to Powertrain Control Module Replacement/Programming in Engine Controls. Is the replacement complete? | -- | -- | |||||
13 | In order to verify your repair, perform the following procedure:
Has the test run and passed? | -- | System OK |
