12 14 600 Replace the knock sensor (N12, N14, N16, N18)

Necessary preliminary work: 

• Switch off ignition.
• Read out fault memory of DME control unit.
• Check stored fault messages.
• Disconnect negative battery cable. See 61 20 900 DISCONNECTING AND CONNECTING BATTERY NEGATIVE LEAD .
• All-wheel drive vehicles only: Remove intake plenum.

Installation location:

The knock sensor is located under the intake air manifold next to the starter motor.

Use a reversible ratchet (1) and extension to release the screw of the knock sensor from below.

Fig 1: Releasing Knock Sensor Screw Using Reversible Ratchet

Courtesy of BMW OF NORTH AMERICA, INC.

Release screw and remove knock sensor (2).

Installation note: 

Clean contact surface of knock sensor on engine block.

Tightening torque 13 62 2AZ .

Fig 2: Locating Knock Sensor Screw

Courtesy of BMW OF NORTH AMERICA, INC.