Bionics
Bionics allow a Chaos Space Marine who has suffered a disabling injury or mutation to return to service. Bionic replacements will function just like the limb or organ they have replaced but there is a chance that an attack or shot will hit a bionic part and be deflected. Any wound suffered may therefore be ignored on a roll of 6. Wounds which allowed no armour save or with a Strength which is at least twice the victim's unmodified Toughness cannot be ignored as they will destroy the bionic components as easily as flesh. If the model has the 'Favour of Khorne' ability then Bionics will have no effect.
Errata — Chapter Approved: Codex: Chaos Space Marines Q&A (v3.0): This should reference Feel No Pain — there is no ability actually named "Favour of Khorne" in the Codex.