The Knock Sensor (KS) is a crucial component that provides information to the
Engine Control Module (ECM) about detonation in the engine. If knock is detected, the ECM will retard the ignition timing to prevent internal mechanical damage. The KS sensor also allows the ECM to optimize ignition timing based on various factors. If low-grade fuel is used, the ECM will compromise engine power output for safe operation. To optimize performance, it is recommended to use a quality grade of fuel as specified in the owner's manual. Testing for KS malfunctions should be done using a BMW service tester or suitable Data Scan Tool (DST) to check for stored faults. When removing and installing the KS, it is important to torque it to specification and apply a locking agent to the threads. The KS sensors are located on the left side of the engine block. Disconnecting various components and plugs, noting their locations and routing, is necessary for removal and installation. Finally, tighten the KS to the specified torque, reconnect the water pipe and knock sensor plugs, and reinstall the wire duct and upper intake manifold.