P0218

Circuit Description

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

^ No ECT DTCs P0116, P0117 or P0118.
^ No TFT DTCs P0711, P0712 or P0713.
^ The engine coolant is greater than 0°C (32°F).

Conditions for Setting the DTC

One of the following cases occur:

Case 1: The transmission fluid temperature is greater than 130°C (266°F) for 30 minutes.

Case 2: The transmission fluid temperature is greater than 144°C (291°F) for 32 seconds.

Action Taken When the DTC Sets

^ The PCM does not illuminate the malfunction indicator lamp (MIL).
^ IDLE ENGINE TRANSMISSION HOT message displays on the driver information center (DIC).
^ The PCM stores DTC P0218 in PCM history.

Conditions for Clearing the DIC/DTC

^ The PCM clears the DIC message when the condition no longer exists.
^ The transmission fluid temperature must be less than 129°C (264°F) for more than 5 seconds.
^ A scan tool can clear the DTC from PCM history.
^ The PCM clears the DTC from PCM history if the vehicle completes 40 warm-up cycles without a non-emission related diagnostic fault occurring.

Diagnostic Aids

^ Inspect the transmission cooling system for possible blockage and restrictions.
^ Ensure that the transmission fluid is at the proper level.

Test Description

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.
^ Vehicle: Was the vehicle used to low excessive weight?
^ Fluid.
^ Filter: Replace the filter if the filter is cracked or not seated.
^ Scavenger Screens: Refer to Unit Repair.
^ Low Line Pressure: Inspect cooler lines for any crimps or restrictions.
^ Radiator.