Circuit Description
The flow of transmission fluid starts in the bottom pan and is drawn through the filter, control valve body assembly, transmission case and into the oil pump assembly. The oil pump assembly pressurizes the fluid and directs it to the pressure regulator valve where it becomes the main supply of fluid to the various components and hydraulic circuits in the transmission. Hot fluid exiting the torque converter flows through the converter clutch apply valve and into the transmission cooler lines to the oil cooler located in the vehicle radiator (and auxiliary cooler if equipped). From the cooler, fluid returns to cool and lubricate the front of the transmission. In forward drive ranges, D4 fluid from the manual valve is routed through an orificed cup plug in the rear of the transmission case to feed the rear lube fluid circuit.
When the vehicle control module (VCM) detects a high transmission fluid temperature (TFT) for a long period of time, then DTC P0218 sets. DTC P0218 is a type D DTC.
Conditions for Running the DTC
| • | No TFT sensor DTCs P0711, P0712 or P0713. |
| • | The ignition switch is in the RUN position for 5 seconds. |
Conditions for Setting the DTC
The TFT is greater than 130°C (266°F) for 600 seconds (10 minutes).
Action Taken When the DTC Sets
| • | The VCM does not illuminate the malfunction indicator lamp (MIL). |
| • | The VCM freezes shift adapts from being updated. |
| • | The VCM stores DTC P0218 in VCM history. |
Conditions for Clearing the DTC
| • | A scan tool clears the DTC from VCM history. |
| • | The VCM clears the DTC from VCM history if the vehicle completes 40 warm-up cycles without a non-emission-related diagnostic fault occurring. |
| • | The VCM cancels the DTC default actions when the fault no longer exists and the ignition switch is OFF long enough in order to power down the VCM. |
Diagnostic Aids
| • | The TFT displayed on the scan tool should rise steadily to a normal operating temperature, then stabilize. |
| • | Ask about the customer's driving habits, trailer towing, etc. Trailer towing should occur in D3. |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
Step | Action | Value(s) | Yes | No | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
1 | Was the Powertrain On-Board Diagnostic (OBD) System Check performed? | -- | Go to Powertrain On Board Diagnostic (OBD) System Check (4.3L) or Powertrain On Board Diagnostic (OBD) System Check (5.0L and 5.7L) in Engine Controls | |||||||
2 |
Important: Before clearing the DTC, use the scan tool in order to record the Failure Records. Using the Clear Info function erases the Failure Records from the VCM. Was the fluid checking procedure performed? | -- | Go to Transmission Fluid Check | |||||||
Was a condition found? | -- | |||||||||
4 | Perform the line pressure check procedure. Refer to Line Pressure Check . Was a condition found? | -- | ||||||||
5 | Inspect the torque converter stator for damage. Refer to Torque Converter Diagnosis . Was a condition found? | -- | Go to Diagnostic Aids | |||||||
6 | Perform the following procedure in order to verify the repair:
Has the test run and passed? | -- | System OK |
