2010 Cadillac CTS Sedan AWD V6-3.6L Page 1192
* Perform the Diagnostic System Check - Vehicle (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic System
Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Strategy Based Diagnosis) for an
overview of the diagnostic approach.
* Diagnostic Procedure Instructions (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/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 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 valve assembly which has no serviceable parts.
Conditions for Running the DTC
* Ignition voltage is 8.6 volts or greater.
* The TFT is -39 to +149掳C (-38 to +300掳F) for 5 seconds.
Conditions for Setting the DTC
The TFT is greater than 140掳C (284掳F) for 1 minute.
Action Taken When the DTC Sets
DTC P0218 is a Type C DTC.
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 transmission fluid temperature
reaches 132掳C (270掳F). The Transmission Fluid Temperature parameter 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 (See: Transmission and Drivetrain/Automatic Transmission/Transaxle/Description and
Operation/Transmission General Description)
* Transmission Indicators and Messages (See: Transmission and Drivetrain/Automatic Transmission/Transaxle/Description and
Operation/Transmission Indicators and Messages)
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions (See: Diagnostic Trouble Code Descriptions/Powertrain Diagnostic Trouble Code
(DTC) Type Definitions)
Circuit/System Verification
1. Review the Failure Records when the DTC set. Verify the engine coolant temperature was less than 125掳C (257掳F).
瀚慖f greater than the specified range, refer to Engine Overheating (LF1, LLT) (See: Engine, Cooling and Exhaust/Cooling System/Testing
and Inspection/Symptom Related Diagnostic Procedures/Engine Overheating)Engine Overheating (LSA) (See: Engine, Cooling and
Exhaust/Cooling System/Testing and Inspection/Symptom Related Diagnostic Procedures/Engine Overheating).
2. Inspect the transmission cooling system for restrictions or damage.
3. Perform the Transmission Fluid Level and Condition Check (See: Transmission and Drivetrain/Automatic Transmission/Transaxle/Testing
and Inspection/Initial Inspection and Diagnostic Overview/Transmission Fluid Level and Condition Check) to verify correct fluid level and
condition.
4. Perform the Transmission Fluid Cooler Flushing and Flow Test (See: Maintenance/Fluids/Fluid - A/T/Testing and Inspection) , to verify
