I wasn't 100% sure about my relay test so I replaced it since it was cheap. Cleared the codes and they came back. So I suspected the check valve could be bad and replaced it (Pierburg). Cleared the codes and they came back again. I had previously removed the pump and connected it to 12VDC direct and it spins fine so I am scratching my head how that could be bad. This is a 2004 E53 3.0i manual trans and so the check valve does NOT have the vacuum line as the earlier models had with some other device in an unfriendly-to-replace location. Any wisdom on what to test next? I am throwing a P0491 and P0492. Thanks. T