101F01

BMW covers 101F01 in SI B11 09 19 (June 2019), a dealer-technician bulletin for every N55 car, together with 28A0. The bulletin's own wording for both is a throttle valve opening angle versus intake pipe absolute pressure comparison that is too high; other tools and code libraries print 101F01 as an air mass plausibility fault, so one fault can wear two names. The warning light is on and one of the two codes is stored.

Scenario A in the bulletin is the code appearing only after programming or after a battery reset for an unrelated repair. The adaptation procedure comes first, before any part: disconnect the tank ventilation (purge) valve connector, idle the engine for 15 minutes, reconnect, clear the faults and test drive. Scenario B is the code without that history, or when scenario A failed: run the test plan, and if it is inconclusive, measure crankcase pressure (the bulletin has the technician slightly loosen the oil fill cap if there is an unusual noise), smoke-test the intake system and the crankcase ventilation, and inspect the front crankshaft seal. With both wastegate vacuum hoses removed from the vacuum reservoir, smoke from the nipples means the cylinder head cover has a micro-crack, since the reservoir is part of it. The bulletin says the engine may need to be hot or cold depending on when the fault stores, and not to replace the DME. These are dealer procedures, with a hot engine in some steps; they are not an owner job.

The owner reports show how hard it can be. A 2026 F10 535i thread describes five months of 101F01: a valve cover replaced, repeated smoke testing, the MAF and both MAP sensors cleaned and swapped, the intake manifold gaskets replaced; the car felt better and the code stayed away for three days and then came back. Replies in the F10 thread: one owner with the same code fixed it by replacing a broken seal on the TMAP sensor of the charge pipe, and suggests checking fuel trim and the pre-cat oxygen sensor; another says a smoke test shows only obvious leaks and that a pressurised test with soapy water is needed to find small ones, which is a forum view against the bulletin's smoke-test step. One F30 owner traced his to combustion blow-by at an injector port and later broken spark plugs, and calls it a rare case. bmv.parts lists the same code on N63, B46 and B58 engines and gives vacuum or charge-pipe leaks, the MAP sensor, crankcase ventilation leaks and a dirty MAF as the causes.