Diagnostic Aids

Check harness routing for a potential short to ground in 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.

TEMPERATURE-TO-RESISTANCE VALUES ⁽¹⁾⁽²⁾

Temperature: °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.

Fig 1: Code 79 Schematic ("C", "K" & "P" Series) Transmission Fluid Temperature High

Fig 2: Code 79 Schematic ("G" Series) Transmission Fluid Temperature High

Fig 3: Code 79 Flow Chart (All Models) Transmission Fluid Temperature High