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Diagnose/P0031
P0031Low SeverityEmissions

O2 Sensor Heater Circuit Low Voltage (Bank 1, Sensor 1)

What This Means

The oxygen sensor heater circuit on bank 1, sensor 1 is reading low voltage. This usually indicates a short to ground in the heater circuit wiring.

Common Symptoms

  • Check engine light on
  • Extended warm-up emissions
  • Minor performance impact
  • May fail emissions test

Common Causes

  • Short to ground in heater wiring
  • Failed O2 sensor heater element
  • Corroded connector
  • Damaged wiring harness
  • PCM ground fault

Estimated Repair Cost

$100 – $350
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.