BMW Exhaust System Explained
Image: BMW 1 Series Complete 76MM Exhaust System with Sports CAT for F20, F2X models, for £598.49, at mtautoparts.com Your BMW's exhaust system does considerably more than carry fumes away from the engine. It has to move exhaust gases safely underneath the car, reduce harmful emissions, control the amount of noise reaching the outside world, and work with a collection of sensors and electronic systems that monitor what is happening inside the exhaust. On an older BMW, the system can be relatively straightforward. On a newer diesel, there can be a diesel oxidation catalyst, DPF, SCR catalyst, AdBlue injection, NOx sensors, temperature sensors and pressure sensors all working together. Petrol BMWs can also have several catalysts, oxygen sensors and, on some newer models, a petrol particulate filter. That is why an exhaust fault isn't always as simple as finding a hole in the pipe. Understanding what each component does makes it much easier to work out what a warning light means...