Such a condition may be requested by the routine based on an evaluation of emission control device performance, and based on a fixed number or {HEAD ~ time} of {TAIL ~ engine and vehicle operation} 
Such a condition may be requested by the routine based on an evaluation of emission control device performance , and based on a fixed number or { HEAD ~ time } of { TAIL ~ engine and vehicle operation }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL