For 1990-2009 cars

### DTC P0711 - TFT Sensor Performance

### Circuit Description

The engine coolant temperature (ECT) sensor, intake air temperature (IAT) sensor and transaxle fluid temperature (TFT) sensor are thermistors that vary resistance according to changes in engine coolant, air induction and transaxle fluid temperature. The powertrain control module (PCM) supplies a 5-volt reference through a pull-up resistor to each sensor, which are connected to ground. When each sensor is cold it has high resistance, high signal voltage at PCM. As sensor temperature increases, its resistance decreases, lower signal voltage at PCM. The PCM uses the signal voltage to determine engine coolant, air induction and transaxle fluid temperature. DTC P0711 sets when the transaxle fluid temperature is above a calibrated temperature, below a calibrated voltage, based on IAT temperature when vehicle has been started cold. A cold start is determined when ECT and IAT readings are within a certain temperature of each other. This DTC is a rational check of the TFT sensor.

### DTC Parameters

DTC P0711 will set if TFT sensor temperature is greater than 9°C plus IAT sensor temperature when:

• | Vehicle is in a cold soak, ECT and IAT temperature are within +/- 6°C (11°F) of each other

• | Condition exists for longer than 2 seconds

• | IAT is less than 40°C (104°F)

• | No ECT, IAT, P0710, P0712, P0713, P0714 DTCs have been set

DTC P0711 diagnostic runs once per ignition cycle once the above conditions have been met.

DTC P0711 is a type A DTC.

### Diagnostic Aids

Important: If DTC P1635 is also set, diagnose that DTC first. A short to ground/short to voltage on the 5-volt reference circuit may set this DTC.

Important: DTC P0711 cannot be cleared until the TFT sensor passes at least one warm-up cycle. Refer to DTC Parameters for specific requirements.

DTC P0711 indicates a skewed TFT sensor or decreased sensor circuit resistance.

Transaxle fluid leaking from the sensor into the sensor connector will cause a shorted condition across the sensor terminals resulting in an elevated temperature.

DTC P0711 may set if the vehicle is towed with the front wheels on the ground. If this is suspected, clear the DTC and return vehicle to the customer.

ECT, IAT and TFT SENSOR RESISTANCE VALUES vs TEMPERATURE
Temperature | SENSOR RESISTANCE (OHMS)
--- | ---
-40°C (-40°F) | 77k-109k
-29°C (-20°F) | 39k-53k
-18°C (0°F) | 21k-27k
-7°C (20°F) | 11k-15k
4°C (40°F) | 6.6k-8.4k
16°C (60°F) | 3.9k-4.5k
27°C (80°F) | 2.4k-2.7k
38°C (100°F) | 1.5k-1.7k
49°C (120°F) | 0.98k-1.1k
60°C (140°F) | 650--730
72°C (160°F) | 430--480
83°C (180°F) | 302--334
94°C (200°F) | 215--235
105°C (220°F) | 159--172
120°C (248°F) | 104--113
140°C (284°F) | 63--68