Z4 bmw with code po442 evap emission control sys. leak detected small leak.

SOURCE: 98 buick regal ls - po442 obd code

Usually the source of the leak is the gas cap (either loose or defective) but if that doesn't apply to your issue then the canister is next to the gas tank.

SOURCE: obd2 reader code po442 evaporative emission

check gas cap and make sure on good, if possible find another one to try on car to see if that works clear codes before trying(take neg cable off battery for approx ten minute) or might have leak in vaccume line or canister

SOURCE: Evap Emissions Leak

This can be because the Gas cap is not holding the pressure. I would start there first.

SOURCE: po410 secondary air injection system malfunction

Two of the more common problems with Auroras.
P0442 - There is a small solenoid (about $30.00) mounted near the L.R. wheel that will fix this.
P0410 - Usually due to leaking Air Injection Valves. These are about 2" square, one near the passenger side firewall, the other near the drivers side radiator. They cost about $200.00/ea. most people just leave it go as it does not effect performance.

SOURCE: code po442 Evaporative emission control system

You can inspect the hoses on the EVAP system for cracks or broken connections, but a smoke test that fills the system with actual smoke is the correct way to check for a leak. The leak can be as small as .040 inches.