SOME VEHICLES MAY EXPERIENCE A ROUGH IDLE WITH THE MIL ON AND DTC P0015 / P0524 STORED IN MEMORY. • P0015:00 - EXHAUST CMP TIMING OVER-RETARDED • P0524:00 - ENGINE OIL PRESSURE TOO LOW THIS IS CAUSED BY A DROP IN ENGINE OIL PRESSURE DUE TO A PIECE OF FOREIGN OBJECT STUCK ON THE OIL PUMP PRESSURE RELIEF VALVE OR OCV. THE TEMPORARY ENTRY OF THE FOREIGN OBJECT TRIGGERS A MIL ILLUMINATION, BUT ROUGH IDLE WILL NOT BE PRODUCED UNTIL A LATER TIME.