1214600 Removing/replacing knock sensors (N52, N52K, N51)

WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2011 BMW 328xi, 2011 BMW 328i, 2010 BMW 328xi, 2010 BMW 328i, and 2009 BMW 328xi. However, it is still accessible from the selected car via links, so may be relevant.

IMPORTANT: Aluminium-magnesium materials.
No steel screws/bolts may be used due to the threat of electrochemical corrosion.
A magnesium crankcase requires aluminium screws/bolts exclusively.
Aluminium screws/bolts must be replaced each time they are released.
Aluminium screws/bolts are permitted with and without color coding (blue).
For reliable identification:
Aluminium screws/bolts are not magnetic.
Jointing torque and angle of rotation must be observed without fail (risk of damage).

Necessary preliminary tasks:

Read out fault memory of DME control unit
Turn off ignition
Disconnect BATTERY NEGATIVE LEAD
Remove INTAKE PLENUM

Unlock plug (1) and remove.

Fig 1: Identifying Plug

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

Installation:

Replace aluminium screws.

Tightening torque 12 14 1AZ .

Fig 2: Locating Knock Sensors

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Installation:

Clean support face of knock sensors on engine block.

Fig 3: Locating Contact Surface Of Knock Sensors On Engine Block

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NOTE: Check stored fault messages.
Delete fault memory.