Home >> BMW >> 2013 >> 135is 2D Convertible, Standard Trans >> Repair and Diagnosis >> Engine Performance >> System >> Self Diagnosis - N55 - Diagnostic Trouble Codes - DTC P0234 (BMW DTC 120208) Through DTC P10F6 (BMW DTC 135B12) >> DTC P0030; BMW DTC 12B104: Oxygen-sensor heater before catalytic converter, activation: open circuit >> Fault code