Circuit DescriptionThe engine control module (ECM) monitors the NOx concentration in the engine’s exhaust gases using an aftertreatment intake NOx sensor and an aftertreatment outlet NOx sensor. By comparing these two values, the ECM is able to determine the conversion efficiency of the SCR catalyst and dosing system. Component LocationThe SCR catalyst is located in the vehicle’s exhaust system, after the diesel particulate filter and decomposition tube. Conditions for Running the DiagnosticsThis diagnostic has to meet specific engine and aftertreatment conditions to run and complete. Conditions for Setting the Fault CodesThe Engine Control Module (ECM) detected the NOx conversion efficiency...

Circuit DescriptionThe aftertreatment SCR (selective catalytic reduction) temperature sensor module is a smart device that communicates with the engine control module via the J1939 data link. The aftertreatment SCR temperature sensor module performs its own internal diagnostics and reports malfunctions back to the engine control module using the J1939 data link. The aftertreatment SCR temperature sensor module is used to measure the aftertreatment SCR intermediate temperature and aftertreatment SCR outlet temperature. The temperature probes are permanently attached to the aftertreatment SCR temperature sensor module and can not be replaced individually. Component LocationThe aftertreatment SCR temperature sensor module is mounted on...

Circuit DescriptionThe aftertreatment fuel injector is electronically controlled by the engine electronic control module (ECM) through a pulse width modulated (PWM) signal. The amount of fuel injected is determined by how long the PWM signal to the injector is on. Component LocationThe aftertreatment fuel injector is installed in the exhaust system in the turbocharger adapter pipe. The aftertreatment fuel pressure sensor and aftertreatment fuel shutoff valve are installed in the shutoff valve manifold. The aftertreatment purge air actuator is located above the shutoff valve manifold. Conditions for Running the DiagnosticsThis diagnostic runs during active regeneration of the aftertreatment diesel particulate...

Circuit DescriptionThe ECM calculates an aftertreatment diesel particulate filter flow resistance, using the aftertreatment diesel particulate filter differential pressure and calculated exhaust flow rate. Component LocationThe aftertreatment diesel particulate filter is located in the exhaust system and is installed by the original equipment manufacturer (OEM). Refer to the OEM service manual. Conditions for Running the DiagnosticsThis diagnostic only runs after successful completion of an active regeneration of the aftertreatment diesel particulate filter. Conditions for Setting the Fault CodesThe Engine Control Module (ECM) calculated the aftertreatment diesel particulate filter flow resistance was too low after successful regeneration of the aftertreatment diesel...

Circuit DescriptionThe injector solenoid valves control fueling quantity and injection timing. The engine control module (ECM) energizes the solenoid by closing a high-side and a low-side switch. Each injector circuit has a dedicated low-side switch that completes the circuit path to ground inside the ECM. Component LocationThe engine harness connects the ECM to the pass-through connector(s) that are located in the rocker housing. Internal injector harnesses are located under the valve cover and connect the injectors to the engine harness at the pass-through connector(s). Conditions for Running the DiagnosticsThis diagnostic runs continuously when the engine is running. Conditions for Setting...