P0218 - Transmission High Temperature Operation Activated

Theory of Operation

The DTC is intended as an informational DTC to aid the technician in determining the root cause of a customer dirveability issue. The DTC is also intended to alert the technician to determine if a cooling system malfunction has occurred or if an additional transmission air to oil cooler is needed to support the customers driving behavior.

When Monitored and Set Conditions

When Monitored:

• This diagnostic runs continuously when the Engine is running.

Set Conditions:

• Transmission temperature exceeds 116° C or 240° F

Default Actions:

• Overheat shift schedule is activated.

Possible Causes

HIGH TEMPERATURE OPERATION ACTIVATED
TORQUE CONVERTER CLUTCH SLIPPING / NOT ACTIVATING
OPERATING VEHICLE WITH TRANSMISSION IN LIMP-IN MODE FOR AN EXTENDED PERIOD OF TIME
RESTRICTED TRANSMISSION COOLER OR COOLER LINE
TRANSMISSION BYPASS COOLER VALVE (THERMOSTAT)
EXCESSIVE TIME IDLING IN GEAR

Always perform the Transmission PRE-DIAGNOSTIC TROUBLESHOOTING PROCEDURE before proceeding. (Refer to 28 - DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure).

HIGH TEMPERATURE OPERATION

NOTE: This DTC is an informational DTC designed to aid the Technician in diagnosing shift quality complaints.
NOTE: This DTC indicates that the transmission has been operating in the "Overheat" shift schedule which may generate a customer complaint.
NOTE: The customer driving patterns may indicate the need for an additional transmission oil cooler.
NOTE: If the Transmission has experienced a catastrophic failure, the Transmission Cooler must be replaced.
1. Verify proper Engine cooling system operation which would affect proper transmission operation.
2. Verify proper operation of the Transmission Bypass Cooler Valve (Thermostat). (Refer to 07 - Cooling/Transmission/COOLER, Transmission Oil/Operation) .
3. Verify the Transmission Cooler and Cooler Lines are not restricted.
4. Verify proper torque converter clutch operation.
5. With the scan tool, check the Event Data to help identify the conditions in which the DTC was set.

Were any of the above problems identified as the probable cause?

Yes
• Repair the cause of transmission overheating. Perform the PRELIMINARY CHECKS procedure. (Refer to 07 - Cooling - Diagnosis and Testing) . Make sure to check for any Service Bulletins pertaining to this problem.
• Perform the TRANSMISSION VERIFICATION TEST. (Refer to 28 - DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure).

No
• Perform the TRANSMISSION VERIFICATION TEST. (Refer to 28 - DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure).
• Test Complete.