Diagnostic Aids

Scan tester displays transmission fluid temperature in degrees Centigrade. After transmission is running, the displayed temperature should rise steadily to about 100°C then stabilize. A faulty connection or an open in ground circuit or signal circuit will result in a Code 59. Test the transmission sensor at various temperature levels to determine if sensor is out of calibration. An out-of-calibration sensor could result in firm shifts or TCC enabled complaint. If code is intermittent, see INTERMITTENTS in TESTS W/O CODES article in this section.

Fig 1: Code 59 Schematic (4L60-E) Transmission Fluid Temperature Low

Fig 2: Code 59 Flow Chart Transmission Fluid Temperature Low