Cumminz

Circuit DescriptionThe aftertreatment DEF dosing valve is controlled by the aftertreatment DEF controller. When the engine ECM commands DEF dosing, the DEF controller sends a pulse width modulated (PWM) signal to the dosing valve, which opens the dosing valve and allows DEF to be sprayed into the exhaust stream. Component LocationThe aftertreatment DEF dosing valve is installed in the exhaust system. It is mounted directly to the aftertreatment decomposition tube, before the Selective Catalytic Reduction (SCR) catalyst. Installation position will vary, based on the aftertreatment architecture and the OEM. Conditions for Running the DiagnosticsThis diagnostic runs when the DEF dosing...

Circuit DescriptionThe diesel exhaust fluid dosing unit lines are responsible for transporting diesel exhaust fluid between the dosing unit, dosing valve, and diesel exhaust fluid tank. Component LocationThere are three diesel exhaust fluid lines. One line is between the dosing unit and dosing valve, and the other two lines are between the dosing unit and diesel exhaust fluid tank. These lines can be partially hidden from view by the Selective Catalytic Reduction (SCR) system and other vehicle components. Line routing will vary, based on the aftertreatment architecture and OEM. Conditions for Running the DiagnosticsThis diagnostic runs continuously when the keyswitch...

Circuit DescriptionThe DEF dosing unit supplies DEF to the aftertreatment nozzle through the nozzle supply line. Component LocationThere are three DEF lines. One line is between the dosing unit and aftertreatment nozzle, and the other two lines are between the dosing unit and DEF tank. These lines can be partially hidden from view by the selective catalytic reduction (SCR) system and other vehicle components. Line routing will vary, based on aftertreatment architecture and the original equipment manufacturer (OEM). Conditions for Running the DiagnosticsThis diagnostic runs continuously while the SCR system is dosing DEF into the aftertreatment system. Conditions for Setting...

Circuit DescriptionThe mass air flow sensor is a frequency based device. A constant voltage is applied to a heated wire. This wire is positioned in the air stream and is heated by the electrical current that the voltage produces. As air flows across it, it cools down. The heated wire or film is a positive temperature coefficient (ptc) resistor. This means that the resistance drops when the temperature drops. The drop in resistance allows more current to flow through it in order to maintain the programmed temperature. This current is changed to a frequency which is sent to the ECM...

Circuit DescriptionThe aftertreatment diesel exhaust fluid controller provides a 5 volt supply and a ground to the aftertreatment diesel exhaust fluid pressure sensor. The pressure sensor provides a signal to the aftertreatment diesel exhaust fluid controller on the sensor signal circuit. This sensor signal voltage changes, based on the aftertreatment diesel exhaust fluid pressure supplied by the dosing unit. The afterteatment diesel exhaust fluid controller will detect a low signal voltage at low diesel exhaust fluid pressures, and a high signal voltage at high diesel exhaust fluid pressures. Component LocationThe aftertreatment diesel exhaust fluid pressure sensor is internal to the...