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Diagnose/P0177
P0177Low SeverityFuel System

Fuel Composition Sensor Circuit Range/Performance

What This Means

The fuel composition sensor readings are outside the expected operating range. This sensor detects ethanol content in flex-fuel vehicles to adjust fuel delivery for different fuel blends.

Common Symptoms

  • Check engine light on
  • Poor performance with E85
  • Fuel economy changes
  • Hard starting

Common Causes

  • Faulty fuel composition sensor
  • Wiring damage
  • Connector corrosion
  • Contaminated sensor
  • PCM circuit issue

Estimated Repair Cost

$100 – $400
Parts and labor (varies by vehicle and location)
Difficulty:Moderate

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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.