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Diagnose/P0117
P0117Medium SeverityEngine

Engine Coolant Temperature Sensor Circuit Low Input

What This Means

The Engine Coolant Temperature (ECT) sensor is sending a low voltage signal indicating very high coolant temperature. This sensor tells the computer how hot or cold the engine is, which affects fuel mixture, ignition timing, and transmission shift points.

Common Symptoms

  • Incorrect temperature gauge reading
  • Poor fuel economy
  • Hard starting
  • Electric fans running incorrectly

Common Causes

  • Faulty ECT sensor
  • Damaged wiring or connector
  • Corroded terminals
  • Short circuit in harness
  • Low coolant level exposing sensor

Estimated Repair Cost

$75 – $300
Parts and labor (varies by vehicle and location)
Difficulty:Easy

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For informational purposes only. Diagnostic trouble codes are starting points for diagnosis, not definitive answers. Always consult a certified mechanic for proper diagnosis and repair. Estimated costs vary by vehicle, location, and shop rates.