Automatic Transmission - Diagnosis - CD4E: Maintenance Mercury Cougar VIII

Transmission Fluid Temperature Sensor

The Transmission Fluid Temperature (TFT) sensor is located on the solenoid valve body. The PCM monitors voltage across the TFT thermistor to determine transaxle fluid temperature. Depending on temperature, the PCM controls line pressure, shift scheduling and TCC operation. Malfunction of sensor will cause incorrect line pressure and possible lack of TCC operation.

PCM Reset

After a PCM reset procedure, the following conditions will be met

1. All DTCs cleared from PCM memory.
2. All freeze frame data cleared from PCM memory.
3. All oxygen sensor test data cleared from PCM memory.
4. OBD-II system monitor status is reset.
5. DTC P1000 set in PCM memory.

To perform PCM reset using NGS tester, ensure connectors are properly connected. Program NGS tester using the following steps

1. Select vehicle and engine selection menu.
2. Select year, engine, model and any additional information requested by NGS tester (optional).
3. Follow operating instructions from NGS tester menu.
4. Select GENERIC OBD-II FUNCTIONS. Press CONT button if monitors are not complete.
5. Turn ignition on.
6. Select CLEARING DIAGNOSTIC CODES.

All DTCs should now be cleared from PCM memory. If problem has not been corrected or fault is still present, hard DTCs will immediately be reset in PCM memory.