ERROR CODE P1477 - Leakage Diagnostic Pump Reed Switch Did Not Open
1) Locate the leakage diagnosis pump, attached to the carbon canister under a black plastic cover between the fuel tank and the spare tire well, under the car.
2) Check for power to the pump on a red/white wire - battery voltage with car running from fuse 3 in the engine fuse carrier in the electronics box in the engine compartment.
3) Check for power on the control wire, brown/blue going to the Motronic control unit
4) Check the signal wire, black/green. When the control wire is grounded, the signal wire should show battery voltage out of the switch inside the pump.
5) Check the signal wire has continuity to pin 34 of the Montonic control unit and that the control wire has continuity to pin 30.
6) On the small vaccuum hose to the leakage diagnosis pump, check for intake manifold vaccuum with the car running.
Four E46's had this same error code.
*3 E46's had the Leak Detection Pump (LDP) Vaccuum Hose Repaired (in other words the vaccuum hose was loose or broken at the intake manifold)
*1 E46 had the intake manifold vaccuum line replaced
I got this info directly from a BMW mechanic so if you ask any questions i probably wont know the answer....!