Mass air flow warning: flow too high

[trebnamo]

I have a 2015 M235i from new that has been trouble-free for the entire time I've owned it, but it threw me a surprise yesterday.

Driving 150+ miles in the hot weather and in very stop/start traffic for an hour or so on M40/M25, the car suddenly makes a clunk noise and afterwards starts being a bit rumbly under load. I'm almost home and I get an orange "Drivetrain" warning on the dashboard. Then a bigger warning "Possible to continue journey. Full performance not available. Have the problem checked by your Service Partner."

Get home, plug in OBD Bluetooth and get the fault code: "P00BD Powertrain - Mass or Volume Air flow A Circuit Flow Too High".

Has a piece of the infamous BMW plastic under the bonnet gone pop? I looked under the bonnet and I guess it could be any of this:



Nothing obviously damaged or loose. I'm reluctant to take it to a dealer in case the answer is "new engine sir". Any ideas how I can get a better idea of diagnosing what happened? It has to go from Surrey to North Wales in a fortnight so I'm concerned about it being match fit

[bigdom]

It's highly unlikely to be the engine. I'd skip the dealer, and have a chat with a local specialst as they are more used to fixing older cars.

You mention Surrey, personally i use https://twgautomotive.co.uk/ in Camberley. They might not be close to you, so have a look at the directory at the top of the page.

[trebnamo]

Thanks for the recommendation and I think you're right about going to a specialist - I think I'm going to Birds as they are closer to me and they have had the car before, just gave them a call and they can fit me in next week. Will take it easy until then, and looks like I'll need to hire a car for Wales.