P0218

Circuit Description with 4T80-E Automatic Transaxle

Transmission Fluid Overtemperature Schematic:

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 up, the sensor resistance becomes lower. The PCM uses TFT information to control Torque Converter Clutch (TCC) apply and release, line pressure, and shift time. The TFT range is from -40°C to +151°C (-40°F to +305°F).

If the PCM detects a high transmission fluid temperature for an extended period of time on the TFT sensor circuit, then DTC P0218 sets. DTC P0218 is a type C DTC.

CONDITIONS FOR RUNNING THE DTC
The transmission fluid temperature is -38°C to 143°C (-36° to 289°F).

CONDITIONS FOR SETTING THE DTC
The transmission fluid temperature is greater than 132°C (270°F) for 10 minutes.

ACTION TAKEN WHEN THE DTC SETS
^ The PCM does not illuminate the Malfunction Indicator Lamp (MIL).
^ TRANSMISSION HOT message displays on the driver information center (DTC).
^ The PCM freezes transmission adapt functions.
^ The PCM records the operating conditions when the Conditions for Setting the DTC are met. The PCM stores this information as Failure Records.
^ The PCM stores DTC P0218 in PCM history.

CONDITIONS FOR CLEARING THE DTC/DTC
^ The PCM clears the DTC message when the condition no longer exists.
^ The transmission fluid temperature is less than 130°C (266°F) for 5 seconds.
^ A scan tool can clear the DTC.
^ The PCM clears the DTC from PCM history if the vehicle completes 40 warm-up cycles without a non-emission-related diagnostic fault occurring.
^ The PCM cancels the DTC default actions when the fault no longer exist and/or the ignition switch is OFF long enough in order to power down the PCM.

DIAGNOSTIC AIDS
^ Ask the customer about overloading the vehicle, exceeding the trailer-towing limit, or towing in Overdrive.
^ Ensure that the transmission fluid is at the proper level.
^ Inspect the transmission cooling system for possible blockage and restrictions.

TEST DESCRIPTION

Steps 1 - 4:

The numbers below refer to the step numbers on the diagnostic table:
2. This step ensures that the transmission fluid is at the proper level. A low fluid level may cause an overtemperature condition.
3. This step inspects or repairs the following items:
^ Engine: Refer to the Cooling and Radiator.
^ Vehicle: Was the vehicle used to tow excessive weight?
^ Fluid: Refer to Transmission Fluid Checking Procedure. Transmission and Drivetrain
^ Filter: Replace the filter if the filter is cracked or not seated. Refer to Fluid Filter Replacement.
^ Scavenger Screens: Refer to Transmission Overhaul Procedure. Transmission and Drivetrain
^ Low Line Pressure: Inspect cooler lines for any crimps or restrictions. Refer to Line Pressure Check Procedure. Transmission and Drivetrain
^ Radiator: Refer to the Cooling and Radiator.