Abstract: Methods and systems are provided for cleaning a urea-clogged diesel exhaust fluid (DEF) injector included in a selective catalytic reduction (SCR) engine exhaust after-treatment system. In one example, a method may include, responsive to a diagnostic code indicating a clogged DEF injector, operating an engine in a DEF injector cleaning mode comprising operating the engine at a high idle speed, activating a DEF pump to deliver a desired amount of DEF at a desired flowrate, and measuring a duty cycle of DEF pump activation during DEF delivery. Responsive to the duty cycle being greater than a threshold duty cycle for a duration, DEF flow restoration is indicated.

Abstract: Methods and systems are provided for cleaning a urea-clogged diesel exhaust fluid (DEF) injector included in a selective catalytic reduction (SCR) engine exhaust after-treatment system. In one example, a method may include, responsive to a diagnostic code indicating a clogged DEF injector, operating an engine in a DEF injector cleaning mode comprising operating the engine at a high idle speed, activating a DEF pump to deliver a desired amount of DEF at a desired flowrate, and measuring a duty cycle of DEF pump activation during DEF delivery. Responsive to the duty cycle being greater than a threshold duty cycle for a duration, DEF flow restoration is indicated.

Abstract: A fuel vapor leak detection assembly (10) having a pressure sensor (20) which is adapted to be selectively and operatively positioned within a fuel fill vent hose (22) in a non-on-board refueling vapor recovery system and which detects fuel vapor leaks. The pressure sensor (20) includes a generally rectangular housing portion (44) and a terminal portion (42) which communicatively connects the sensor (20) to a controller. A conventional pressure sensing device (56) is contained within housing portion (44). Sensor (20) further includes two opposed, generally hollow vent line connection ends or portions (46), (48) which connect to vent hose (22). Portions (44), (46), and (48) cooperatively form a generally cylindrical pressure sensing passageway (54) in which pressure sensing device (56) resides, thereby allowing the device (56) to accurately sense and measure the value or amount of fuel vapor pressure traveling through passageway (54).