The P0441 code indicates that the engine control module has detected an incorrect flow of fuel vapors from the charcoal canister to the intake manifold. This typically occurs when the purge valve does not operate as commanded or there is a restriction in the vacuum lines.
The purge valve may be stuck open or closed, preventing the correct amount of vapor from entering the engine.
Cracked, kinked, or clogged vacuum lines can restrict or leak the flow of vapors during the purge cycle.
A saturated or obstructed canister can prevent the proper flow of fuel vapors to the intake.
Leaks in the vacuum plumbing between the purge valve and the intake manifold can cause incorrect flow readings.
Internal electronic failure of the control module, though this is extremely rare for this specific code.
The definition is universal; the diagnostics are engine-specific. Open your vehicle for the codes documented for it:
Usually no; loose gas caps typically trigger leak-related codes like P0442 or P0455 rather than purge flow codes.
No; it is very rare for the PCM to be the cause of P0441. The issue is almost always a mechanical failure of the purge valve or a hose leak.
Yes, the vehicle will typically remain drivable, although fuel efficiency may drop and it will not pass an emissions test.