Home >> BMW >> 2012 >> 335i 2D Convertible, Standard Trans >> Repair and Diagnosis >> Engine Performance >> System >> Self Diagnosis - N55 - Diagnostic Trouble Codes - DTC P0478 (BMW DTC 138101) Through DTC P0440 (BMW DTC 191D01) >> DTC P0324; BMW DTC 168A20: Knock control, fault check: malfunction, system fault >> Action in service