Diagnostic Aids
Scan tester displays transmission temperature in degrees Centigrade. After transmission is running, the displayed temperature should rise steadily to about 212°F (100°C) then stabilize. A faulty connection or an open in circuit No. 455 or circuit No. 1227 will result in a Code 59. Test the coolant sensor at various temperature levels to determine if sensor is out of calibration. See the TRANSMISSION SENSOR RESISTANCE table. An out-of-calibration sensor could result in firm shifts, or TCC enabled complaint.