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DFI ECM Tests W/Codes: Action:

ECM turns on "ENGINE CONTROL SYSTEM" light. ECM commands BCM to display "SERVICE SOON" message on CCDIC panel. ECM substitutes 110°C for transmission temperature.

The transmission temperature sensor a variable thermistor that varies its resistance depending on temperature. The sensor is a 2-wire sensor with a reference signal coming from the ECM to sensor on pin "A" on circuit No. 520. and a sensor reference ground pin "B" of circuit No. 476.

As temperature of sensor increases, its resistance decreases. As sensor resistance decreases, the voltage signal from the ECM decreases due to less voltage drop across temperature sensor. High temperature will result in low signal voltage on circuit No. 520 and low temperature will result in a high voltage signal on circuit No. 520. The ECM uses transmission temperature information to vary Viscous Converter Clutch (VCC) application speeds. Code E059 will set when the ECM sees an excessively low voltage or excessively high VCC temperature when coolant is hot or cold, respectively.

NOTE: Test numbers refer to test numbers on diagnostic chart.
  1. VCC sensor circuit is shorted to ground.
  2. VCC sensor circuit is open.