Diagnostic Instructions
DTC Descriptor
DTC P0218: Transmission Fluid Overtemperature
Diagnostic Fault Information
Component
| Cause
| DTC
|
Transmission
| Vehicle Overload or Beyond Towing Capacity:
| • | Vehicle is towing beyond capacity |
| P0218
|
Heat Transfer:
| • | Cooler restrictions - radiator has restricted flow/blockage |
| • | Aftermarket auxiliary cooler not installed correctly, incorrect flow direction -- reversed flow |
| • | Restricted, blocked, or pinched transmission cooler lines. |
| P0218
|
Vehicle Damage:
| • | Damage to vehicle under carriage |
| • | Transmission bottom pan damage |
| P0218
|
Transmission Fluid:
| • | Contaminated or poor fluid quality |
| P0218
|
Torque Converter:
| • | Torque converter failure -- stator, pump, clutch, ballooning or heat damaged |
| • | Excessive brake torque maneuvers |
| P0218
|
Low Pump Output:
| • | Blocked, damaged or loose filter |
| • | Pinched or restricted cooler lines |
| • | Restricted cooler -- damage or debris |
| • | Inefficient pump -- worn |
| P0218
|
Clutch Slippage:
| P0218
|
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 9.0 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 135°C (275°F) or greater for 4 minutes.
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 DRIVE (D). Ensure the engine cooling system is functioning normally.
Reference Information
Schematic Reference
Description and Operation
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
- Review the Failure Records when the DTC set. Verify the engine coolant temperature is less than 125°C (257°F).
- Inspect the transmission cooling system for restrictions or damage.
- Perform the
Transmission Fluid Check to verify correct fluid level and condition.
- Perform the
Transmission Fluid Cooler Flushing and Flow Test to verify proper transmission oil cooler flow.
- Perform the
Line Pressure Check to verify proper transmission line pressure.
- 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 after completing the diagnostic procedure.
Perform the
Service Fast Learn Adapts following all transmission related repairs.
