2F08 is a fault stored in your BMW's memory (an ISTA fault code, not a standard OBD-II P-code).
What it means: DME — intake air temperature (IAT) sensor signal implausible. On most engines the IAT is built into the mass-air-flow (MAF) sensor. Usually a dirty/faulty MAF, a loose connector or an intake/vacuum leak — can cause rough or jittery idle. Not dangerous to drive; check/clean the MAF sensor and its plug, and inspect the intake for leaks.
