Circuit Description
Transmission oil cooling begins with pump suction drawing oil from the main case bottom pan, through the filter, the valve body assembly and into the main case. Oil is also drawn in the from adapter case bottom pan. The oil pump assembly pressurizes the oil and directs it to the pressure regulator valve where it becomes the main supply of oil to the various components and hydraulic circuits. Hot oil exiting the torque converter through the apply oil circuit flows to the converter clutch control valve and into the transmission cooler lines to the oil cooler located in the vehicle radiator. From the cooler, oil returns to cool and lubricate the main and adapter case components through the overdrive (OD) and main case lube circuits.
When the TCM detects high transmission oil temperature, then DTC P0218 sets. DTC P0218 is a type C DTC.
Condition for Running the DTC
The ignition switch is in the RUN position.
Condition for Setting the DTC
The TFT is greater than 165°C (329°F) for 19.9 seconds.
Action Taken When the DTC Sets
| • | The TCM does not illuminate the malfunction indicator lamp (MIL). |
| • | The TCM will use a defaulted transmission temperature of 130°C (266°F). |
| • | The TCM freezes shift adapts from being updated. |
| • | The TCM stores DTC P0218 in TCM history. |
Conditions for Clearing the DTC
| • | A scan tool clears the DTC from TCM history. |
| • | The TCM clears the DTC for TCM history if the vehicle completes 40 warm-up cycles without a non-emission-related diagnostic fault occurring. |
| • | The TCM cancels the DTC default actions when the fault no longer exists. |
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 number below refers to the step numbers on the diagnostic table.
Step | Action | Value(s) | Yes | No | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
1 | Did you perform the Transmission On-Board Diagnostic (OBD) System Check ? | -- | ||||||||||
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 ECM/TCM. Refer to Transmission Fluid Check . Did you perform the Transmission Fluid Checking Procedure? | -- | Go to Transmission Fluid Check | |||||||||
3 | Inspect the engine cooling system for the following overheating conditions:
Did you find the condition? | -- | Go to Engine Overheating | |||||||||
Inspect the transmission cooling system for the following conditions:
Did you find the condition? | -- | |||||||||||
5 | Inspect the cooler lines for restrictions or a blocked cooler. Did you find the condition? | -- | ||||||||||
6 | Inspect the main case and adapter case bottom pan for damage (large dents.) Did you find the condition? | -- | ||||||||||
7 | Inspect the main case oil filter for:
Did you find a condition? | -- | ||||||||||
8 | Inspect the torque converter for stator damage. Refer to Torque Converter Diagnosis . Did you find and correct the condition? | -- | ||||||||||
9 |
Did you find and correct the condition? | -- | -- | |||||||||
10 | Perform the following procedure in order to verify the repair:
Does the TFT remain below 165°C (329°F)? | -- | System OK |
