1993 Chevrolet C3500 HD 6.5 F, StandardFACTORY OEM SERVICE PROCEDURE

DTC 14, ECT Sensor - High Temperature Indicated (With A/T): Notes

The Engine Coolant Temperature (ECT) sensor uses a thermistor to control signal voltage from ECM. The ECM applies and monitors voltage over circuit No. 410 to sensor. When engine is cold, sensor resistance is high, the ECM will sense a high signal voltage. As engine warms, sensor resistance becomes less and voltage drops. At normal engine operating temperature, voltage will be 1.5-2.0 volts. When DTC 14 sets, early application of torque converter clutch will occur.

NOTE: Test numbers refer to numbers on diagnostic chart.
  1. DTC 14 will set if signal voltage indicates a coolant temperature greater than 293Β°F (145Β°C) for 0.5 second.
  2. This test determines if circuit No. 410 is shorted to ground, causing conditions for DTC 14 to set.
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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.

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