VEHICLES MAY EXHIBIT A MALFUNCTION INDICATOR LAMP (MIL) ON WITH A DIAGNOSTIC TROUBLE CODE (DTC) P0401 AND/OR P1408 STORED IN MEMORY. THIS MAY BE CAUSED BY A LOSS OF VACUUM TO THE EXHAUST GAS RECIRCULATION SYSTEM BECAUSE THE RUBBER VACUUM ELBOW (LOCATED ON THE BACK SIDE OF THE INTAKE MANIFOLD) HAS BEEN SEATED AGAINST THE VACUUM PORT.