6T70/6T75 - Automatic Transmission
DTC P0218
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Initial Inspection and Diagnostic Overview) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Initial Inspection and Diagnostic Overview) provides an overview of each diagnostic category.
DTC Descriptor
DTC P0218
- Transmission Fluid Overtemperature
Circuit/System Description
The primary source of heat in the transmission is the torque converter. Hot oil exits the torque converter through the torque converter clutch (TCC) control valve and flows to the transmission cooler supply line. The supply line connects to the cooler, which is in the radiator. From the cooler, the oil returns through the oil cooler return line and enters the lubrication circuits. After lubricating the internal components, the oil returns to the oil pan. The transmission fluid temperature (TFT) sensor is located in the control solenoid (w/body and TCM) valve assembly.
Conditions for Running the DTC
* The ignition voltage is between 8.6 volts and 19.0 volts.
* The TFT is -39 to +149°C (-38 to +300°F) for 5 seconds.
Conditions for Setting the DTC
The TFT is 140°C (284°F) or greater for 1 minute.
Action Taken When the DTC Sets
* DTC P0218 is a Type C DTC.
* The TCM freezes transmission adaptive functions.
Conditions for Clearing the DTC
DTC P0218 is a Type C DTC.
Diagnostic Aids
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.
Reference Information
Description and Operation
Transmission General Description (Transmission General Description)
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions (Diagnostic Trouble Code Descriptions)
Scan Tool Reference
Control Module References (Programming and Relearning) for scan tool information
Circuit/System Verification
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 (Engine Overheating).
2. Inspect the transmission cooling system for restrictions or damage.
3. Perform the Transmission Fluid Check (Transmission Fluid Check) to verify correct fluid level and condition.
4. Perform the Transmission Fluid Cooler Flushing and Flow Test (Automatic Transmission Oil Cooler Flushing and Flow Test) to verify proper transmission oil cooler flow.
5. Perform the Line Pressure Check (Line Pressure Check) to verify proper transmission line pressure.
6. 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.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
Important: Perform the Service Fast Learn Adapts (Programming and Relearning) any time a transmission related component is serviced.