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Diagnose/P0387
P0387High SeverityEngine

Crankshaft Position Sensor B Circuit Low Input

What This Means

The secondary crankshaft position sensor B voltage is below the minimum expected threshold. Some engines use a second crank sensor for redundancy or more precise timing measurement.

Common Symptoms

  • Intermittent stalling
  • Hard starting
  • Misfires
  • Check engine light on

Common Causes

  • Failed crank sensor B
  • Wiring damage
  • Reluctor wheel issue
  • Connector corrosion
  • PCM circuit failure

Estimated Repair Cost

$150 – $500
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.