This particular code is becoming more and more common, and most diagnostic trouble trees will send you chasing a ghost in or around the purge solenoid and plumbing.

Current models using NVLD (Natural Vacuum Leak Detection) as opposed to the earlier LDP (leak Detection Pump) use NGC controllers that use purge as a means of fuel trim and the NVLD switch as a means to signal purge flow, so a P0441 often results when the actual issue is a sticking switch inside the NVLD.

These type problems are often highly intermittent, so the NVLD system will test fine when forcing the monitor or testing the switch for pulling a vacuum on the system manually. You might also see general evap failure codes (P0440) for this same reason and continue testing for leaks to find no issues.

While restricted lines could also result in this code, the NVLD issues are much more common. A handheld vacuum pump at the filter end of an NVLD on a sealed system should trip the switch at a level of 1" Hg.

Thomas from New York