12 14 600 Removing/replacing knock sensors (N52, N52K, N51)

2009 BMW 528i AutomaticSECTION 12 14 600 Removing/replacing knock sensors (N52, N52K, N51)
IMPORTANT: Aluminium-magnesium materials.Β 
No steel screws/bolts may be used due to the threat of electrochemical corrosion.
A magnesium crankcase requires aluminum screws/bolts exclusively.
Aluminum screws/bolts must be replaced each time they are released.Β 
The end faces of aluminum screws/bolts are painted blue for the purposes of reliable identification.
Jointing torque and angle of rotation must be observed without fail (risk of damage).Β 

Necessary preliminary tasks:Β 

  • Read out fault memory of DME control unit
  • Switch off ignition
  • Disconnect battery negative lead
  • Remove AIR INTAKE MANIFOLD

Unlock plug (1) and remove.

Fig 1: Identifying Plug
G04751293Courtesy of BMW OF NORTH AMERICA, INC.

Release screws on both knock sensors (1) and remove knock sensors (1).

Installation:Β 

Replace aluminum screws.Β 

Tightening torque 12 14 1AZ .

Fig 2: Identifying Knock Sensors
G04751294Courtesy of BMW OF NORTH AMERICA, INC.

Installation:Β 

Clean support face of knock sensors on engine block.

Fig 3: Removing Knock Sensors
G04748562Courtesy of BMW OF NORTH AMERICA, INC.
RENDER: 1.0x

NO RELATED

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • β€’ You smell fuel, burning insulation, or see smoke.
  • β€’ Brakes feel soft, pull hard to one side, or make grinding noises.
  • β€’ The engine overheats, stalls repeatedly, or misfires under load.
  • β€’ You are missing required tools, torque specs, or safe lifting equipment.
  • β€’ You are not confident in the next step or safety outcome.