2ML70 - Automatic Transmission

DTC P0218

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (Diagnostic System Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Strategy Based Diagnosis) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Diagnostic Procedure Instructions)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 drive motor generators. The drive motor generators are cooled by the transmission fluid. Hot fluid exits the drive motor generators and flows to the transmission fluid cooler pipe assembly. The transmission fluid cooler pipe assembly connects to the cooler, which is in front of the radiator. The transmission fluid cooler pipe assembly is equipped with an internal thermostat that opens at 80°C (176°F) for optimum transmission operation and fuel economy. The transmission fluid cooler pipe thermostat is part of the transmission fluid cooler pipe assembly, located near the transmission and is not serviced separately. From the cooler, the fluid returns through the transmission fluid cooler pipe assembly and enters the lubrication circuits. After lubricating the internal components, the fluid returns to the oil pan. The sensor is located in the control solenoid valve assembly and is not serviced separately.

Conditions for Running the DTC

The transmission fluid temperature is at least -50 (-58°F) and no more than +150°C (+302°F) for 10 seconds.

Conditions for Setting the DTC

The transmission fluid temperature is greater than 135°C (275°F) for 300 seconds.

Action Taken When the DTC Sets

* P0218 is a Type B DTC.
* The driver information center may display 'TRANSMISSION HOT - Idle Engine'.

Conditions for Clearing the DTC

P0218 is a Type B DTC.

Diagnostic Aids

* The driver information center will display 'TRANSMISSION HOT- Idle Engine' with an audible chime when the transmission fluid temperature is greater than 150°C (302°F). The message and chime will not turn off until the transmission fluid temperature is less than 150°C (302°F) and the ignition is Off long enough for the TCM to power down.
* Ask about the customer's driving habits, trailer towing, etc.
* Verify the engine cooling system is functioning normally.
* The hybrid powertrain control module will reduce drive motor generator torque at temperatures greater than 160°C (320°F). Drive motor generator torque is reduced to zero if the temperature reaches 190°C (374°F).
* Review with the customer their driving habits, trailer towing, etc. Verify the engine cooling system and transmission cooling system is functioning normally.

Reference Information
Description and Operation

Electronic Component Description (Electronic Component Description)
DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions (Powertrain Diagnostic Trouble Code (DTC) Type Definitions)
Scan Tool Reference

Control Module References (Control Module References)for scan tool information.

Circuit/System Verification

1. Verify that P0711, P0712, or P0713 is not set.

• If DTC P0711, P0712, or P0713 is set, Refer to DTC P0711, P0712, or P0713 (2ML70 - Automatic Transmission).

2. Ignition ON, observe the scan tool ECM engine coolant temperature (ECT) parameter in the freeze frame data. The reading should be below 125°C (257°F).

• If the ECT was above 125°C (257°F) when the DTC set, refer to Engine Overheating (Engine Overheating).

3. Ignition ON, observe the scan tool Trans. Fluid Temp. parameter in the freeze frame data. The reading should be below 135°C (275°F).

• If greater than the specified range, refer to Automatic Transmission Overheating (Automatic Transmission Overheating).

4. If neither the engine nor the transmission had an over temperature condition when the DTC set, replace the Q8 control solenoid valve assembly.

Repair Instructions

Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.

Control Module References (Control Module References)for Control Solenoid Valve Assembly replacement, programming and setup.

Repair Verification

1. With a scan tool, clear the DTCs.
2. Operate the vehicle long enough to ensure the engine has reached normal operating temperature and the transmission fluid temperature has stabilized between 80-98°C (176-208°F).
3. Observe the specific DTC P0218, and verify DTC P0218 has run and passed.