Recently got a Service Engine Soon light and fault read:

27B8 Differential pressure sensor, intake manifold, plausibility

2004 545i with 115k miles.

Didn't notice any change in how the car drove. Even my mechanic said he'd have to do a little research. Cleared the fault and I am will be bringing it back in a few days.

Any ideas or similar experiences?

 

Item#4 in the diagram.
Not much help but I did find this information.(hopefully not TMI) You might have your mechanic check the EGR valves on top of the valve covers while he's at it. Good luck with the repair!

The MAP sensor checks for variations in intake-manifold pressure. When everything is functioning normally, vacuum varies depending on engine speed and load. The MAP sensor relays this manifold-vacuum information to the engine's computer, which then regulates fuel and spark accordingly.

Also

MAP stands for ?Manifold Absolute Pressure?, which is the pressure inside the engine?s intake manifold. Pressure is low when intake vacuum is high (as at idle), and pressure is high when vacuum is low (as at wide-open throttle). It?s called an ?absolute? pressure reading because it depends solely on pressure inside the manifold, though some types of MAP sensors are actually ?differential? pressure sensors that measure the difference between intake vacuum and atmospheric (barometric) pressure.

 

I got this same error but dont have idea what is it, I have changed MAP sensor but error still came back. Write something if your service do the job.