For 1990-2009 cars
Automatic Transmission Components
Automatic Transmission Controls Schematics
OBD II Symbol Description Notice

### 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 D 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 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 and the ignition switch is OFF long enough in order to power down the TCM.

### 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.

1. This step checks for air flow restrictions or damage which may result in the transmission overheating.

#### DTC P0218 Transmission Fluid Overtemperature

Step | Action | Value(s) | Yes | No
--- | --- | --- | --- | ---
1 | Was the Powertrain On-Board Diagnostic (OBD) System Check performed? | -- | Go to Step 2 | Go to On-Board Diagnostic System Check
2 |

1. Install the Scan Tool .
2. With the engine OFF, turn the ignition switch to the RUN position.

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.

3. Record the DTC Failure Records.
4. Clear the DTC.
5. Perform the transmission fluid checking procedure.

Refer to Transmission Fluid Check

Was the fluid checking procedure performed?

--

Go to Step 3

Go to Transmission Fluid Check

3 | Inspect the engine cooling system for the following overheating conditions:

• | Low coolant level

• | Air flow restrictions

• | Air flow blockage

• | Debris

Was the condition found?

--

Go to Engine Overheating

Go to Step 4

4 | Inspect the transmission cooling system for the following conditions:

• | Air flow restrictions

• | Air flow blockage

• | Debris

• | Damaged cooler lines

Was a condition found?

--

Go to Oil Cooler Pipes Replacement .

Go to Step 5

5 | Inspect the cooler lines for restrictions or a blocked cooler. Was a condition found? | -- | Go to Transmission Fluid Cooler Flushing and Flow Test | Go to Step 6
6 | Inspect the main case and adapter case bottom pan for damage (large dents.) Was the condition found? | -- | Go to Changing Fluid and Oil Filter | Go to Step 7
7 | Inspect the main case oil filter for:

• | Damage

• | Restrictions

• | Missing gasket

• | Loose Mounting

Was a condition found?

--

Go to Changing Fluid and Oil Filter

Go to Step 8

8 | Inspect the torque converter for stator damage. Refer to Torque Converter Diagnosis . Did you find and correct the condition? | -- | Go to Step 10 | Go to Step 9
9 | Inspect the valve body for a stuck pressure regulator valve. Inspect the valve body for a leaking pressure regulator valve. Did you find and correct the condition? | -- | Go to Step 10 | --
10 | Perform the following procedure in order to verify the repair:

1. Select DTC.
2. Select Clear Info.
3. Operate the vehicle long enough to ensure normal transmission temperature.

Does the TFT remain below 165°C (329°F)?

--

System OK

Go to Step 1