Fuel-pressure sensor
Reports fuel pressure so delivery can be controlled.
In a fuel rail or supply circuit.
A pressure-sensitive element produces a signal the controller compares with the desired pressure.
A gauge feeding back to the pump’s supervisor.
Pressure plausibility faults can also reflect a real supply problem or wiring defect.
Plugs and filters use engine-specific service guidance. Pumps and injectors are normally assessed through pressure, leakage and electrical tests.
Spark-plug service is usually less involved than direct-injector or high-pressure-pump replacement; coding and access can add work.
BMW low-pressure and rail-pressure sensors measure different circuits and are not interchangeable.
BMW combustion models; spark components are petrol-only and glow-plug hardware is diesel-only.