Diagnostic Instructions
DTC Descriptor
DTC P0218: Transmission Fluid Overtemperature
Diagnostic Fault Information
Component
| Cause
| DTCs
|
Engine
|
| • | Engine coolant level low |
| • | Incorrect engine coolant |
| • | Old coolant or incorrect concentration level |
| • | Radiator hose kinked or pinched |
| • | Loose, missing, or damaged radiator air seals or deflector -- poor air flow |
| • | The radiator and A/C condenser has air flow obstructions to include large amount of bent fins |
| • | The cooling fans do not operate |
| • | Inspect the engine mechanical for worn, leaking, cracked cylinder heads, or engine block |
| P1258
|
Transmission
| Vehicle Overload or Beyond Capacity Towing:
| • | Vehicle is towing beyond capacity |
| P0218
|
Heat transfer:
| • | Cooler restrictions - radiator has restricted flow/blockage |
| • | Aftermarket auxiliary cooler installed incorrectly, incorrect flow direction -- reversed flow |
| • | Restricted, blocked, or pinched transmission cooler lines. |
| P0218
|
Transmission Abuse:
| • | Excessive brake torque maneuvers |
| • | Vehicle is towing beyond capacity |
| 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 |
| 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 (with body and TCM) valve assembly.
Conditions for Running the DTC
| • | Ignition voltage is at lease 8.6 volts, but no more than 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 greater than 140°C (284°F) for 1 minute.
Action Taken When the DTC Sets
| • | DTC P0218 is a Type C DTC. |
| • | The TCM freezes the transmission adaptive function. |
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 the customer whether their typical day-to-day driving include:
| • | Hauling or vehicle over-loading |
| • | Extreme off-road conditions |
Trailer towing should occur in D4. 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
Circuit/System Verification
- Review the Failure Records when the DTC set.
| ⇒ | If the engine coolant temperature (ECT) was above 125°C (257°F) when the DTC set, go to
Engine Overheating and correct that concern first. |
- Perform the
Transmission Fluid Check to verify correct fluid level and condition.
Circuit/System Testing
- Inspect the transmission cooling system for restrictions or damage, inducing any auxiliary cooler if equipped.
- 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. |
- Perform the
Line Pressure Check to verify proper transmission line pressure.
| ⇒ | If a concern is found repair or replace the damaged components as necessary. |
Repair Instructions
Perform the
Diagnostic Repair Verification after completing the diagnostic procedure.
Repair or replace the automatic transmission cooler or lines as necessary. Refer to:
