CODE 58, TRANSMISSION FLUID TEMPERATURE HIGH - ALL MODELS
Transmission fluid temperature sensor is a thermistor which controls signal voltage to control module. Control module applies and monitors voltage to sensor. When transmission fluid is cold, sensor resistance is high; therefore, control module will see high signal voltage. As transmission fluid warms, sensor resistance and voltage will drop. At normal transmission operating temperature of 212°F (100°C), voltage will be about 1.5-2.0 volts.
Note. Test numbers refer to numbers on diagnostic chart.
- Code 58 will set if signal voltage indicates a transmission fluid temperature greater than 305°F (151°C) for one second.
- This test determines if circuit is shorted to ground, which will result in conditions for Code 58.
Check harness routing for a potential short to ground in TFT signal circuit. Scan tester displays transmission fluid temperature in degrees Centigrade. After transmission is running, temperature display should rise steadily to about 100°C then stabilize. Test transmission sensor at various temperature levels to determine if sensor is out of calibration. See TRANSMISSION SENSOR - TEMP TO RESISTANCE chart. An out-of-calibration sensor could result in delayed shifts or TCC enabled complaint.
| °F (°C) | Ohms |
|---|---|
| 150 (66) | 42-56 |
| 100 (38) | 159-198 |
| 70 (20) | 420-514 |
| 40 (4) | 1308-1609 |
| 20 (-7) | 3088-3941 |
| 0 (-18) | 7902-10,943 |
| 40 (-40) | 73,556-127,857 |
| (1) Measure resistance across sensor terminals. (2) Temperatures are approximates. | |
| (1) | Measure resistance across sensor terminals. |
| (2) | Temperatures are approximates. |
TEMPERATURE-TO-RESISTANCE VALUES (1) (2)
