15457 - Special Coverage. Some 2010-2015 Chevrolet Express and GMC Savana vehicles and 2011-2015 Chevrolet Silverado HD and GMC Sierra HD vehicles that are equipped with 6.6L Duramax Diesel engines (RPO LML or LGH) may contain a leak in the seal between the engine-exhaust down pipe and the engine-exhaust pipe. If a leak is present, the intermittent regeneration of the diesel-particulate filter may cause small amounts of diesel fuel to leak from the vehicle. It may also cause diesel-fuel vapor and engine exhaust to enter the passenger cabin. Dealers are to inspect the turbocharger exhaust pipe and the downpipe connection and implement service kit if necessary.