For 1990-2009 cars

### Circuit Description

The transaxle fluid temperature sensor, engine coolant temperature (ECT) sensor, and the intake air temperature (IAT) sensor are thermistor circuits. When the sensors are cold, they have high resistance and high sensor voltage. As the temperature increases, this resistance and voltage decreases. The PCM supplies a 5-volt signal to the sensors, which is also connected to ground. The PCM reads the voltage drop on the sensor signal lines to determine the corresponding temperature.

### Conditions for Setting the DTC

Important: The transaxle fluid temperature ECT and IAT sensors are continuously checked when the ignition is ON.

Important: Visually inspect the transaxle fluid temperature, ECT, and IAT wires for evidence of shorts to battery/ignition voltage. Shorts to battery/ignition voltage will skew the sensor resistance and cause DTC P0710 and P0711 to set.

DTC P0710 is set when the PCM has detected the following conditions for more than 25.6 minutes:

• | No ground/open in the temperature circuit.

• | No short in the temperature circuit.

• | The temperature value (TV) is less than a calculated temperature based on engine temperature (ET) and intake air temperature (IAT).

### Diagnostic Aids

With the ignition ON and the engine OFF, observe the transaxle fluid temperature vs. ECT vs. IAT sensor after the vehicle obtained a cold soak.

Refer to Description and Operation for transaxle fluid temperature, ECT, and IAT sensors Temperature vs. Resistance chart.

Important: The PCM uses 2 internal circuits to identify transaxle temperature. One circuit is used for temperatures of 48°C (118°F) and below. If either circuit has failed, the DTC will set. However, the temperature may look normal in the other range.

Important: DTC P0711 can not be cleared until the TFT sensor passes at least 1 warm-up cycle. Refer to DTC P0711 parameters for specific requirements.

Test low scale with the engine at room temperature and high scale with the engine at normal operating temperature, above 70°C (158°F).

Degrees (°C) | Degrees (°F) | Sensor Resistance (Ohms)
--- | --- | ---
-40 | -40 | 77k-100k
-29 | -20 | 39k-53k
-18 | 0 | 21k-27k
-7 | 20 | 11k-15k
4 | 40 | 6.6k-8.4k
16 | 60 | 3.9k-4.5k
27 | 80 | 2.4k-2.7k
38 | 100 | 1.5k-1.7k
49 | 120 | 0.98k-1.1k
60 | 140 | 650-730
72 | 160 | 430-480
83 | 180 | 302-334
94 | 200 | 215-235
105 | 220 | 159-172
120 | 248 | 104-113
140 | 284 | 63-68

The following chart lists the possible thermal sensor faults and the associated DTC.

| Sensor Fault
--- | ---
DTC Fault | IAT | ECT | Transaxle Fluid Temperature Sensor
P0710 | Skewed high | Normal | Normal
P0710 | Normal | Skewed high | Normal
P0710 | Normal | Normal | Skewed high