Pattern "B"

In drive cycle pattern "B", EGR and fuel system components are monitored. With engine warm, start engine. Let idle briefly, then accelerate vehicle at a steady rate (throttle must be 1/4 to 1/2 open) to 55 MPH. Release throttle, allowing vehicle speed to drop rapidly for at least 10 seconds. Accelerate back up to 53-60 MPH and hold that speed steady for 5 minutes. Return to idle and turn engine off.