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 Powertrain Control Module (PCM) uses TFT information to control
Torque Converter Clutch (TCC) apply and release, line pressure, and shift
time. The TFT range is -40°C to +151°C (-40°F to +305°F).
When 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 Setting 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). |
Failure Criteria
| • | 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. |
| • | DTC P0218 is stored in the PCM history. |
Conditions for Clearing the DIC/DTC
| • | The PCM turns OFF the DIC after three consecutive
trips without a failure reported. |
| • | 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 the PCM history. The PCM clears
the DTC from the PCM history if the vehicle completes 40 warm-up cycles without
a failure reported. |
| • | The PCM cancels the DTC default actions when the fault no longer
exists and the ignition is OFF long enough in order to power down the PCM. |
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 for the following problems:
| • | Engine: Refer to Cooling and Radiator, Section 6. |
| • | Vehicle: Was the vehicle used to tow excessive weight? |
| • | Filter: Replace the filter if the filter is cracked or not seated.
Refer to Filter Replacement, in On-Vehicle Service. |
| • | Scavenger Screens: Refer to Unit Repair. |
| • | Low Line Pressure: Inspect cooler lines for any crimps or restrictions. |
| • | Radiator: Refer to Cooling and Radiator, Section 6. |
DTC P0218 Automatic 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 A Powertrain On Board Diagnostic (OBD) System Check
|
2
| Have you performed the transmission fluid checking procedure?
| --
|
Go to Step 3
| Go to
Transmission Fluid Check
|
3
| This DTC can only be set if one or
more of the following items is at fault.
| • | 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 |
- Inspect the items.
- Repair the faulty items.
Have you completed the inspection and repair procedure?
| --
|
Go to Step 4
| --
|
4
| In order to verify your repair, perform
the following procedure:
- Select DTC.
- Select Clear Info.
- Operate the vehicle under the following conditions:
| • | Monitor the Automatic Transmission Fluid Temperature. Ensure that
the Automatic Transmission Fluid Temperature remains at or below 129°C
(264°F) for 5 seconds. |
- Select Specific DTC. Enter DTC P0218.
Has the test run and passed?
| --
| System
OK
|
Begin the diagnosis again. Go to Step 1
|
