Transaxle Fluid Temperature/IAT/ECT Sensor

TRANSAXLE FLUID TEMPERATURE/IAT/ECT SENSOR - RANGE/PERFORMANCE - SKEWED SENSOR

The transaxle fluid temperature sensor, engine coolant temperature sensor (ECT) and the intake air temperature sensor (IAT) 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 five-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.

DTC PARAMETERS
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.

^ Temperature value (TV) is less than a calculated temperature based on engine temperature (ET) and intake air temperature (IAT).

DTC P0711 is set when the PCM/TC has completed two warm-up cycles with the following parameters detected:

^ Engine coolant below 30°C (80°F) after exceeding 71°C (160°F).

^ IAT and ECT within 6°C (10°F).

^ Transaxle fluid temperature reading is greater than 9°C (16°F) of the IAT during start-up.

IMPORTANT:
The transaxle fluid temperature ECT and IAT sensors are continuously checked when ignition is On.

NOTICE:
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's resistance and cause DTC P0710 and P0711 to set.

DIAGNOSTIC AIDS
DTC P0711 may set if the vehicle is towed with the front wheels on the ground. If it is suspected that the vehicle has been towed recently, clear the DTC and return vehicle to the customer.

IMPORTANT:
DTC Code P0711 can not be cleared until the TFT sensor passes at least one warm-up cycle.

Refer to P0711 DTC Parameters for specific requirements.

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

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

IMPORTANT:
The PCM uses two 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.

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





The chart lists the resistances of the transaxle fluid temperature IAC and ECT sensors compared to temperature.





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