Transmission fluid is drawn from the bottom pan through the filter, case assembly, channel plate assembly, control valve body assembly, and into the oil pump assembly. The pump is mounted on the control valve body assembly. Fluid pressure leaving the pump is controlled by the pressure regulator valve and becomes the main supply of line pressure to the various components and hydraulic circuits. Hot fluid from the torque converter, the primary source of heat in the transmission, flows through the torque converter clutch (TCC) control valve into the oil cooler supply line. The oil cooler supply line connects to the oil cooler, which is located in the vehicle radiator and auxiliary oil cooler, if equipped. Cool fluid then returns by way of the oil cooler return line to lubricate the final drive assembly and other components along the output shaft. After lubricating the internal components, the oil returns to the oil pan. The TFT sensor, attached to the bottom of the valve body, is part of the internal transmission wire harness and not serviced separately. The normal TFT operating temperature is -40 to +151°C (-40 to +304°F).

The TFT is 140°C (284°F) or greater for 1 minute.

DTC P0218 is a Type C DTC.

The driver information center (DIC), if equipped, will display 'TRANSMISSION HOT- Idle Engine' when the TFT reaches 132°C (270°F). The TFT on the scan tool should rise steadily to a normal operating temperature, and then stabilize. Ask about the customer's driving habits, trailer towing, etc. Trailer towing should occur in DRIVE (D). Ensure the engine cooling system is functioning normally.

Schematic Reference

Automatic Transmission Controls Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Electrical Information Reference

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

Important: Ensure the transmission fluid is at the proper level by performing the Transmission Fluid Check .

1. Ask about the customer driving habits, trailer towing, etc. Trailer towing should occur in D.
2. Review the Failure Records when the DTC set. Verify the engine coolant temperature is less than 125°C (257°F).

⇒	If greater than the specified value, refer to Engine Overheating .

3. Ensure the engine cooling system is functioning normally/properly. The TFT on the scan tool should rise steadily to a normal operating temperature, and then stabilize.
4. Inspect the transmission cooling system for restrictions or damage.
5. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

Important: You must perform the Circuit/System Verification before proceeding with Circuit/System Testing.

1. Inspect for restricted air flow through the radiator and/or auxiliary cooler, if equipped, due to debris or damaged fins.

⇒	If a concern is found, repair or replace the damaged components as necessary.

2. Inspect the transmission cooling system and/or auxiliary cooler, if equipped, for kinked or damaged transmission cooler lines.

⇒	If a concern is found, repair or replace the damaged components as necessary.

3. Perform the Transmission Fluid Cooler Flushing and Flow Test to verify proper transmission oil cooler flow.

⇒	If a concern is found repair or replace the damaged components as necessary.

4. Perform the Line Pressure Check to verify proper transmission line pressure.

⇒	if the line pressure is low, refer to Fluid Pressure High or Low .

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Perform the Service Fast Learn Adapts following all transmission related repairs.