P1278 – Air/Fuel Ratio Sensor Circuit Fault (Nissan)

Description

The ECM detected a circuit malfunction in the AFR sensor on Bank 1.

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Symptoms

  • Hesitation
  • Poor acceleration

Causes

  • Open circuit
  • Short to ground
  • Faulty sensor

Diagnosis

  • Check wiring continuity
  • Inspect connectors
  • Scan live data

Repair

  • Repair wiring
  • Replace sensor