Diagnostic Instructions
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 TFT is -39 to +149°C (-38 to +300°F) for 5 seconds.
Conditions for Setting the DTC
The TFT is greater than 132°C (270°F) 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
Schematic Reference
Automatic Transmission Controls Schematics
Connector End View Reference
DTC Type Reference
Electrical Information Reference
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, refer 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.
- 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
- Repair or replace the automatic transmission cooler or lines as necessary.
- Perform the
Service Fast Learn Adapts
.
Repair Verification
- With a scan tool, clear the DTCs.
- Operate the vehicle long enough to ensure the engine has reached normal operating temperature and the TFT has stabilized between 80-98°C (176-208°F).
- Observe the specific DTC, and ensure DTC P0218 has run and passed.
- Check for any other DTCs that you have not diagnosed.