P1391 – Ignition Coil Primary Circuit Low Voltage (Nissan)

Description

The ECM detected low voltage in the ignition coil primary circuit.

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Symptoms

  • Misfire
  • Hard start

Causes

  • Low battery voltage
  • Wiring issue
  • Coil failure

Diagnosis

  • Check battery voltage
  • Inspect wiring
  • Test coil

Repair

  • Repair wiring
  • Replace coil