Grand Cherokee 2WD V8-4.7L VIN N (2000)
Transmission Position Switch/Sensor: Description and Operation
Transmission fluid temperature readings are supplied to the Powertrain Control Module by the transmission temperature sensor. It is a thermistor located
in the governor pressure sensor connector. The temperature readings are used to control engagement of the overdrive clutch, the converter clutch, and
governor pressure. Normal resistance value for the thermistor at room temperature is approximately 1000 ohms.
The powertrain control module (PCM) prevents engagement of the converter clutch and overdrive clutch, when fluid temperature is below approximately
-1 °C (30 °F).
If fluid temperature exceeds 126 °C (260 °F), the Powertrain Control Module will cause a 4-3 downshift and engage the converter clutch. Engagement is
according to the third gear converter clutch engagement schedule.
The overdrive OFF lamp in the instrument panel, also illuminates when the shift back to third occurs.
The transmission will not allow fourth gear operation until fluid temperature decreases to approximately 110 °C (230 °F).
