Flag 74

Circuit Schematic:

ECT/TRANS TEMP SENSOR RATIO ERROR
The engine coolant temperature (ECT) sensor is a thermistor located in a coolant passage on the engine. When coolant temperature is cold the sensor has a high resistance, as temperature increase the resistance of the sensor decreases. The PCM provides a five volt signal to the coolant sensor, which is also connected to PCM ground. The PCM reads the voltage drop on the signal line to determine coolant temperature.

INFORMATION FLAG PARAMETERS
Information flag 74 will set if:
^ The transmission temperature sensor is functioning properly.
^ The ECT reading is less than Transaxle Temperature Sensor (TTS) reading.

DIAGNOSTIC AIDS
Information flag 74 is used to indicate a degrading ECT.

Remove the ECT and inspect for contamination.

Measure resistance through the ECT by attaching female terminals to the two ECT pins.

The resistance reading should be 2786 ohms ± 40 Ohms at room temperature of 25°C (77°F).

NOTE: Information flags should he used for diagnostic purposes only. They do not necessarily indicate component malfunction/failure.