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

WARNING: This page does not describe the selected car, but rather 14 other vehicles, including the 2008 BMW Z4, 2008 BMW 328xi, 2008 BMW 328i, 2008 BMW 323i, and 2007 BMW Z4. 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.

The end faces of aluminium 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).

Necessary preliminary tasks:

Read out fault memory of DME control unit
Switch off ignition
Disconnect Battery Negative Lead
Remove Intake Air Manifold

Unlock plug (1) and remove.

Fig 1: Identifying Knock Sensor Plug

Courtesy of BMW OF NORTH AMERICA, INC.

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

Installation:

Replace aluminium screws.

For tightening torque refer to 12 14 1AZ in 12 14 ELECTRONIC SHIFT UNITS OR CONTROL UNITS .

Fig 2: Locating Knock Sensors Screws

Courtesy of BMW OF NORTH AMERICA, INC.

Installation:

Clean support face of knock sensors on engine block.

Fig 3: Identifying Knock Sensors Support Face And Cleaning Procedure On Engine Block

Courtesy of BMW OF NORTH AMERICA, INC.

NOTE: Check stored fault messages.

Now clear the fault memory.