'02 Xterra 4x4 S/C in fail-safe mode

[daprie]

OK, here's what I'm up against... the SC and knock sensor were replaced 30k miles ago at the dealership under warranty (had 78k miles on it at the time). Now I'm seeing the same symptoms as before they were replaced. The engine is back in fail-safe mode (P0328 code) and the supercharger is rattling loudly again. We decided to replace the coupler in the SC to see if that helped and it doesn't seem to of. My only thought now is that the SC is gone or the knock sensor needs to be replaced (both of which are quite expensive especially if they have to be done together). Is there anything that I'm missing here? I would hate to think that the SC that the dealer put on was only good for 30k miles. Any help or ideas would be extremely appreciated.

Thanks in advance!