I don't think a frozen pulley can generate a code, at least not until the belt breaks and you loose alternator, etc. if it's been very cold, I would be especially worried about a CCV freezing up which can cause oil to be sucked into the intake and potentially hydro lock the engine. Try to get it somewhere warmer (above freezing) before starting it again.

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David.X5
2001 X5 4.4i Sport
SOLD! at 160k miles