P0218

DTC P0218

Circuit Description

The transmission fluid temperature (TFT) sensor is a positive temperature coefficient thermistor (temperature sensitive resistor) that provides information to the transmission control module (TCM) regarding transaxle fluid temperature. The temperature sensor is located in valve body. Calculated temperature is a factor used to determine the shift time and shift delay time.

The internal electrical resistance of the sensor varies in relation to the operating temperature of the transaxle fluid.

The TCM sends a 5-volt reference signal to the temperature sensor and measures the voltage rise in the electrical circuit. A higher fluid temperature creates a higher resistance in the temperature sensor, thereby measuring a higher voltage signal.

The TCM measures this voltage as another input to help control line pressure, shift schedules and TCC apply. When transaxle fluid temperature reaches 120°C (248°F) the TCM enters "hot mode". At greater temperatures the TCM modifies transaxle shift schedules and TCC apply in an attempt to reduce fluid temperature by reducing transaxle heat generation.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC P0218 Transmission Fluid Overtemperature

Conditions for Setting the DTC

* The calculated temperature is compared with the predetermined min. and max. value.
* If the temperature is less than min. value or greater than max value then the current temperature is regarded as of range and the corresponding error but will be set.

Action Taken When the DTC Sets

* No lamp control required but diagnostic information should be stored immediately when malfunction is detected.
* TCM assumes the transaxle fluid temperature is 60°C (124°F).
* No influence on driveability.

Conditions for Clearing the MIL/DTC

Using a scan tool can clear history DTCs.

Diagnostic Aids

When DTC P0218 sets, the possible cause of fault could be Transaxle Temperature Sensor.