Diagnostic Aids

1993 Chevrolet Suburban C2500, 7.4 NSECTION Diagnostic Aids

Check harness routing for a potential short to ground in circuit No. 1227. Scan tester displays transmission fluid temperature in degrees Centigrade. After transmission is running, the temperature display should rise steadily to about 100Β°C then stabilize. Test the 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. If code is intermittent, see INTERMITTENTS in TESTS W/O CODES article in this section.

Fig 1: CODE 58, Schematic, Trans. Fluid Temp. Sensor - Hi Temp. Indicated (Astro, Safari & "C" & "K" Series)
G93E76392Courtesy of GENERAL MOTORS CORP.
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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • β€’ You smell fuel, burning insulation, or see smoke.
  • β€’ Brakes feel soft, pull hard to one side, or make grinding noises.
  • β€’ The engine overheats, stalls repeatedly, or misfires under load.
  • β€’ You are missing required tools, torque specs, or safe lifting equipment.
  • β€’ You are not confident in the next step or safety outcome.