Engine internals

Crankshaft position sensor

Tells the engine computer the exact crank angle and speed.

Drag to turn it Open in the 3D lab
Where it sits

Facing a toothed wheel on the crankshaft or flywheel.

How it works

A sensor reads passing teeth and a reference gap so the DME can time spark and injection.

Think of it as

A clock’s second hand that the computer reads.

Symptoms when it fails

Stalling, no-start or misfire faults can involve this sensor, its wiring or the trigger wheel.

Lifespan

Usually condition-based rather than a routine replacement. Lubrication, overheating and the exact engine affect wear.

Repair cost

Internal-engine work is usually labor-intensive. Diagnosis and the engine code determine the repair scope.

The BMW angle

BMW DME units compare crank and cam signals continuously and store a correlation fault if they disagree.

Used in

BMW petrol and diesel engines; petrol-only systems are identified individually.

Sources
Same system

Engine internals

Engine blockHolds the cylinders and supports the engine’s rotating parts.Cylinder headCloses the cylinders and carries the valves that control breathing.Cylinder-head gasketSeals combustion pressure, oil and coolant between the block and head.PistonReceives combustion force and moves up and down inside a cylinder.Piston ringsSeal combustion gas and control the oil film on cylinder walls.Connecting rodTransfers piston force to the crankshaft.CrankshaftTurns the pistons’ back-and-forth motion into rotation.Crankshaft main bearingSupports the crankshaft on a controlled film of oil.