P0218

Diagnostic Chart:

Wiring Diagram:

Circuit Description
The Automatic Transmission Fluid Temperature (TFT) sensor is a thermistor within the Automatic Transmission Fluid Pressure Manual Valve Position Switch (TFP Val. Position Sw.). The TFT sensor controls the signal voltage to the PCM. The PCM supplies a 5-volt reference to the sensor on circuit 1227. When the transmission fluid is cold, the sensor resistance is high. The PCM detects high signal voltage. As the transmission fluid temperature increases to a normal operating temperature, the sensor resistance becomes less and the signal voltage decreases.

When the PCM detects a high transmission temperature for a long period of time, then DTC P0218 sets. DTC P0218 is a type D DTC.

Conditions for Setting the DTC

^ No TFT sensor DTCs P0712 or P0713.
^ The TFT is greater than 130°C (266°F).
^ All conditions met for 900 seconds (15 minutes).

Action Taken When the DTC Sets

^ The PCM freezes shift adapts from being updated.
^ The PCM does not illuminate the Malfunction Indicator Lamp (MIL).

Conditions for Clearing the DTC

^ 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 wiring for poor electrical connections at the PCM. Inspect the wiring for poor electrical connections at the transmission 20-way connector. Look for the following conditions:

- A bent terminal
- A backed out terminal
- A damaged terminal
- Poor terminal tension
- A chafed wire
- A broken wire inside the insulation

^ When diagnosing for an intermittent short or open condition, massage the wiring harness while watching the test equipment for a change.
^ The TFT sensor temperature displayed on the scan tool should rise steadily to a normal operating temperature, then stabilize.
^ Inspect the torque converter stator for a possible problem.
^ Ask about the customer's driving habits, trailer towing, etc.

Test Description
The numbers below refer to the step numbers on the diagnostic chart.

3. This step tests for a skewed (mis-scaled) sensor or shorted circuit.
4. This step simulates a TFT sensor DTC P0713.