Code 59, Trans. Temperature Sensor Low Temperature: Notes

1995 Buick Regal Gran SportSECTION Notes

Temperature sensor is a 2 wire thermistor located in transaxle. This sensor operates in the same manner as engine coolant temperature sensor and intake air temperature sensor. PCM applies 5 volts to sensor on signal circuit. Voltage sensed at PCM signal circuit terminal will be high when transmission fluid is cold and as fluid warms voltage signal will drop. A very high signal voltage indicates a low fluid temperature or a failure in sensor circuit. Normal fluid temperature range is 75-100°C.

Code 59 will set when sensor indicates a low temperature for a precalibrated period of time. Malfunction Indicator Light (MIL) will not illuminate and PCM will use a warm default sensor value.

NOTE: Test numbers refer to numbers on diagnostic chart.
  1. This test determines if a current condition exists.
  2. Simulates a Code 58. If PCM recognizes low signal voltage, and scan displays about 146°C or higher, PCM and wiring are okay.
  3. Checks if signal circuit is open. Five volts should be present at sensor connector.
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