MAZDA: MIL COMES ON WITH P2004/CHECK VALVE STUCK OPEN. SOME VEHICLES MAY EXPERIENCE AN MIL THAT COMES ON WITH DTC P2004 (VARIABLE TUMBLE SHUTTER VALVE STUCK OPEN). THE CAUSE MAY BE THE CHECK VALVE IN THE INTAKE MANIFOLD VACUUM CHAMBER BEING STUCK OPEN. CHECK VALVE HAS NOW BEEN UPDATED. *PE