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 flows through the torque converter clutch (TCC) control valve into the cooler lines to the oil cooler located in the vehicle radiator and auxiliary cooler, if equipped. Cool fluid then returns to lubricate the final drive assembly and other components along the output shaft.

The transmission fluid temperature is between -39 and +149°C (-38 and +300°F) for 5 seconds.

The transmission fluid temperature is greater than 130°C (266°F) for 2 minutes.

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 D4. 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

Electronic Component Description for automatic transmission fluid temperature sensor information

Electrical Information Reference

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

1. 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 range, refer to Engine Overheating.

2. Inspect the transmission cooling system for restrictions or damage.
3. Perform the Transmission Fluid Check to verify correct fluid level and condition.
4. Perform the Transmission Fluid Cooler Flushing and Flow Test to verify proper transmission oil cooler flow.
5. Perform the Line Pressure Check to verify proper transmission line pressure.

Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records.

1. Perform the Transmission Fluid Check.

⇒	If the level is not within specifications, repair as necessary.

2. Inspect for the following conditions:

•	Transmission line pressure low--Refer to Line Pressure Check. If the line pressure is low, refer to High or Low Line Pressure.

•	Transmission fluid flow through cooler and/or auxiliary cooler, if equipped, is restricted due to:

-	Transmission fluid level low

-	A clogged filter

-	A leaking filter or seal--Refer to Automatic Transmission Fluid Filter and Seal Replacement.

-	Plugged, kinked or damaged transmission cooler pipes--Refer to Transmission Fluid Cooler Flushing and Flow Test.

•	Air flow through transmission fluid cooler and/or auxiliary cooler, if equipped, is restricted due to:

-	Damaged fins

-

Debris

•	Engine overheating due to:

-	Low coolant level--check coolant temperature, coolant level, and hoses

-	Restricted air flow

-	Restricted coolant flow--Refer to Engine Overheating

Perform the Diagnostic Repair Verification after completing the repair.