Crankshaft (Speed/Position Pulse) Sensor

On E46, sensor is located on rear left side of engine, under exhaust manifold. On all other models, sensor is located on lower right front of engine. It supplies PCM with crankshaft position information. When PCM has determined optimum ignition timing (based on input from various sensors), information supplied by crankshaft (speed/position pulse) sensor is used to signal ignition firing.