40TE GPEC
P0218-HIGH TEMPERATURE OPERATION ACTIVATED
Theory of Operation
If the transmission oil temperature rises above 115° C (240° F), the overheat shift schedule is activated. The DTC is an informational code only and is set to aid the technician in determining a customer driveability issue. The code 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 should be added to the vehicle if the customer regularly drives in a manner that overheats the transmission. Extended operation above 115° C (240° F) will reduce the durability of the transmission and should be avoided. Correcting the cooling system malfunction or installing an additional transmission oil cooler will improve transmission durability especially for customers who operate in city/construction stop and go traffic, tow trailers regularly, drive aggressively in low gear or drive regularly in mountainous areas.
- When Monitored:
Whenever the engine is running.
- Set Condition:
Immediately when an Overheat shift schedule is activated when the Transmission Oil Temperature reaches 115° C (240° F).
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Pre-Diagnostic Troubleshooting Procedure
1. CHECK FOR LIMP-IN OPERATION
1. With the scan tool, check for transmission DTCs which would result in limp-in operation. NOTE: While operating in limp-home mode (due to a ratio error, solenoid continuity or pressure switch fault, etc.) the TCC will not engage. The heat generated within the torque converter will increase significantly (especially during launches). This can result in overheated fluid. Restarting the vehicle hot, when the original fault (which caused limp-in) is no longer present, could cause the P0218 DTC to be set.
Are there any other transmission DTCs present?
Yes
- Testing and Inspection Perform the appropriate diagnostic procedure.
No
- Go To 2
2. CHECK TCC ENGAGEMENT
1. Operate the vehicle and check for proper TCC operation (turbine speed should be equal to engine speed when TCC is fully engaged).
Does the TCC engage properly?
Yes
- Go To 3
No
- Repair the cause of a slipping torque converter.
- Perform the appropriate TRANSMISSION VERIFICATION TEST. .
3. CHECK ENGINE COOLING SYSTEM
1. Perform Engine Cooling System diagnostics Testing and Inspection.
Is the Engine Cooling System functioning properly?
Yes
- Go To 4
No
- Repair the cause of the engine overheating. Refer to the Service Information for the related diagnostic or repair procedures.
- Perform the appropriate TRANSMISSION VERIFICATION TEST. .
4. TRANSMISSION OIL COOLER RESTRICTED
1. Check the Transmission Oil Cooler Flow.
Is the transmission oil cooler restricted or plugged?
Yes
- Repair the cause of the plugged Transmission Oil Cooler as necessary and repair or replace the Transmission Oil Cooler.
- Perform the appropriate TRANSMISSION VERIFICATION TEST. .
No
- Go To 5
5. HIGH TEMPERATURE OPERATION
1. This DTC is an informational DTC designed to aid the Technician in diagnosing shift quality complaints.
2. This DTC indicates that the transmission has been operating in the "Overheat" shift schedule which may generate a customer complaint.
3. The customer driving patterns may indicate the need for an additional transmission oil cooler.
4. With the scan tool, check the Event Data to help identify the conditions in which the DTC was set.
5. Check for any Service Information Tune-ups or Service Bulletins for any possible causes that may apply.
Repair
- Repair the cause of transmission overheating.
- Perform the appropriate TRANSMISSION VERIFICATION TEST. Verification Tests.