DTC 58

Transmission Temperature Sensor Diagnostic Chart:

Transmission Temperature Sensor Circuit:

CIRCUIT DESCRIPTION:
The Transmission Temperature Sensor (TTS) is a thermistor that controls the signal voltage to the PCM/TCM. The PCM/TCM applies voltage on CKT 1227 to the sensor. When the transmission fluid is cold, the sensor resistance is high, therefore, the PCM/TCM will sense high signal voltage.

As the transmission fluid temperature warms, the sensor resistance becomes less and the voltage drops to normal transmission operating temperature 100°C (212°F) the voltage will measure about 1.5 to 2.0 volts.

TEST DESCRIPTION:
Number(s) below refer to circled number(s) on the diagnostic chart.

1. Code 58 will set if:
^ Signal voltage indicates a transmission temperature above 154°C (309°F) for 1 second.

2. This test will determine if CKT 1227 is shorted to around which will cause the conditions for Code 58.


DIAGNOSTIC AIDS: Check harness routing for a potential short to ground in CKT 1227.

"Scan" tool displays transmission temperature in degrees Centigrade. After transmission is running, the temperature should rise steadily to about 100°C then stabilize.

- Intermittent Malfunctions

The temperature to resistance value scale, in figure, may be used to test the transmission sensor at the various temperature levels to evaluate the possibility of a "skewed" sensor. A "skewed" sensor could result in delayed garage shifts or TCC enabled complaints.