P1220 – Knock Sensor 1 Fault (BMW)

Description

P1220 BMW indicates a fault in Knock Sensor 1.

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Symptoms

  • Rattling under load
  • Reduced power
  • Hesitation

Causes

  • Sensor failure
  • Wiring damage
  • Connector corrosion

Diagnosis

  • Check knock sensor signal
  • Inspect wiring
  • Scan DME

Repair

  • Replace knock sensor
  • Repair wiring
  • Clean connector