TSB: Some 2011 ? 2012 CT 200h vehicles may exhibit a vibration due to rough idle and/or tapping noise from HV transaxle at cold start. The Check Engine Light may also illuminate with (DTC) P0401 (Exhaust Gas Recirculation Flow Insufficient Detected). Due to excess carbon build up at the valve assembly, the valve will stick causing the engine RPM to fluctuate. Follow the procedures in this bulletin to address this condition.