Circuit DescriptionThe aftertreatment outlet NOx (nitrogen oxides) sensor is a smart device and communicates with the engine control module (ECM) via the J1939 data link. The aftertreatment outlet NOx sensor performs its own internal diagnostics and reports malfunctions back to the primary ECM using the J1939 data link. The NOx sensor is permanently attached to the NOx control module. They are serviced as a single component and can not be replaced individually. The aftertreatment outlet NOx sensor is used to measure the NOx emissions at the outlet of the aftertreatment system. Component LocationThe aftertreatment outlet NOx sensor location can vary...

Circuit DescriptionThe OEM truck manufacturer can install a permit switch in the dash or send an inhibit message via the J1939 data link to the engine ECM. The function of the inhibit message is to prevent the aftertreatment system from performing mobile regenerations. Component LocationThe aftertreatment diesel particulate filter is located in the exhaust system and is installed by the original equipment manufacturer (OEM). The permit switch can be an actual switch in the vehicle dash or it can be a J1939 message sent via the J1939 data link. Refer to the OEM service manual. Conditions for Running the DiagnosticsThis...

Circuit DescriptionThe coolant temperature sensor is a variable resistor sensor and is used to measure the temperature of the coolant of the engine. The engine control module (ECM) supplies 5 volts to the coolant temperature signal circuit. The ECM monitors the change in voltage caused by changes in the resistance of the sensor to determine the coolant temperature. Component LocationThe engine coolant temperature sensor is located on the thermostat housing. Conditions for Running the DiagnosticsThis diagnostic runs continuously when the engine is running. Conditions for Setting the Fault CodesEngine coolant temperature was less than 60°C [140°F] for over 1 hour...

Circuit DescriptionNormally, switches, accelerators, and other components are connected to the engine control module (ECM) directly through individual wires. Multiplexing allows those same components to be hard wired to an original equipment manufacturer (OEM) vehicle electronic control unit (VECU) or transmission electronic control unit (ECU) in the cab. Then component values and states from components such as sensors, accelerators, and switches can be transmitted from the OEM VECU to the Cummins® ECM over the SAE J1939 data link. Messages sent from OEM VECUs or transmission ECUs are received by the Cummins® ECM and used for controlling the engine. The Cummins®...

Circuit DescriptionNormally, switches, accelerators, and other components are connected to the engine control module (ECM) directly through individual wires. Multiplexing allows those same components to be hard wired to an original equipment manufacturer (OEM) vehicle electronic control unit (VECU) or transmission electronic control unit (ECU) in the cab. Then component values and states from components such as sensors, accelerators, and switches can be transmitted from the OEM VECU to the Cummins® ECM over the SAE J1939 data link. Messages sent from OEM VECUs or transmission ECUs are received by the Cummins® ECM and used for controlling the engine. The Cummins®...