DTC P0218 Transmission Fluid Overtemperature. Cadillac Eldorado 1999

For 1990-2009 cars only

Makes 🢒 Cadillac 🢒 1999 🢒 Eldorado 🢒 Transmission/Transaxle 🢒 Automatic Transaxle - 4T80-E 🢒 DTC P0218 Transmission Fluid Overtemperature

Automatic Transmission Components
Automatic Transmission Controls Schematics
OBD II Symbol Description Notice

Circuit Description

The automatic transmission fluid temperature (TFT) sensor is a negative coefficient thermistor. When the transmission fluid is cold, the sensor resistance is high. As the transmission fluid warms up, the sensor resistance becomes lower. The PCM uses TFT information to control torque converter clutch (TCC) apply and release, line pressure, and shift time. The TFT range is from -40°C to +151°C (-40°F to +305°F).

If the PCM detects a high transmission fluid temperature for an extended period of time on the TFT sensor circuit, then DTC P0218 sets. DTC P0218 is a Type C DTC.

Conditions for Running the DTC

•	No ECT DTCs P0116, P0117 or P0118.

•	No TFT DTCs P0711, P0712 or P0713.

•	The engine coolant is greater than 0°C (32°F).

Conditions for Setting the DTC

One of the following cases occur:

Case 1: The transmission fluid temperature is greater than 130°C (266°F) for 30 minutes.

Case 2: The transmission fluid temperature is greater than 144°C (291°F) for 32 seconds.

Action Taken When the DTC Sets

•	The PCM does not illuminate the malfunction indicator lamp (MIL).

•	IDLE ENGINE TRANSMISSION HOT message displays on the driver information center (DIC).

•	The PCM stores DTC P0218 in PCM history.

Conditions for Clearing the DIC/DTC

•	The PCM clears the DIC message when the condition no longer exists.

•	The transmission fluid temperature must be less than 129°C (264°F) for more than 5 seconds.

•	A scan tool can clear the DTC from PCM history.

•	The PCM clears the DTC from PCM history if the vehicle completes 40 warm-up cycles without a non-emission related diagnostic fault occurring.

Diagnostic Aids

•	Inspect the transmission cooling system for possible blockage and restrictions.

•	Ensure that the transmission fluid is at the proper level.

Test Description

The numbers below refer to the step numbers on the diagnostic table:

This step ensures that the transmission fluid is at the proper level. A low fluid level may cause an overtemperature condition.

This step inspects or repairs the following items:

•	Engine: Refer to the Cooling and Radiator Section.

•	Vehicle: Was the vehicle used to tow excessive weight?

•	Fluid: Refer to Transmission Fluid Check .

•	Filter: Replace the filter if the filter is cracked or not seated. Refer to Transmission Fluid Filter Replacement .

•	Scavenger Screens: Refer to Unit Repair.

•	Low Line Pressure: Inspect cooler lines for any crimps or restrictions. Refer to Line Pressure Check .

•	Radiator: Refer to the Cooling and Radiator Section.

DTC P0218 Transmission Fluid Overtemperature

Step

Action

Value(s)

Yes

Was the Powertrain On-Board Diagnostic (OBD) System Check performed?

Go to Step 2

Go to Powertrain On Board Diagnostic (OBD) System Check

Was the Transmission Fluid Checking Procedure performed?

Go to Step 3

Go to Transmission Fluid Check

This DTC can only be set if one or more of the following conditions occur:

•	An overheated engine

•	An overloaded vehicle

•	Fluid that has become contaminated with antifreeze

•	A clogged filter or a filter that is not seated correctly

•	Clogged scavenger screens

•	Low line pressure caused by clogged or restricted cooler lines

•	A restricted radiator

Inspect for the conditions above.
Repair any of the above items as necessary.

Is the repair complete?

Go to Step 4

Perform the following procedure in order to verify the repair:

Select DTC.
Select Clear Info.
Operate the vehicle under the following conditions:

•	Road test the vehicle.

•	Monitor the automatic transmission fluid temperature. Ensure that the automatic transmission fluid temperature remains at or below 129°C for 5 seconds.

Select Specific DTC. Enter DTC P0218.

Has the test run and passed?

System OK

Go to Step 1