Circuit DescriptionThe aftertreatment selective catalytic reduction (SCR) catalyst is monitored by SCR intake and SCR outlet temperature sensors that are located in the aftertreatment system. The intake temperature sensor is located before the catalyst and the outlet temperature sensor is located at the outlet of the catalyst system. Component LocationThe SCR catalyst is located in the exhaust system. The location of the SCR catalyst can vary depending on the original equipment manufacturer (OEM). Refer to the OEM service manual for detailed engine and component identification. Conditions for Running the DiagnosticsThe engine must be turned OFF for period of 8 hours...

Circuit DescriptionThe SCR temperature sensors are used to monitor the temperatures of the exhaust gas entering and exiting the SCR catalyst. Component LocationThe SCR intake and outlet exhaust temperature sensors are located in the aftertreatment system. The intake temperature sensor is located before the SCR catalyst and the outlet temperature sensor is located at the outlet of the SCR catalyst. Conditions for Running the DiagnosticsThe engine must be turned off for period of 8 hours before this diagnostic will run. This diagnostic runs when the keyswitch is turned to the ON position after an 8 hour cold soak. Conditions for...

Circuit DescriptionThe SCR intake temperature sensor is used by the electronic control module (ECM) to monitor the engine exhaust temperature entering the SCR catalyst. The ECM monitors the voltage on the SIGNAL pin and converts this to a temperature value. Component LocationThe SCR intake temperature sensor is located in the aftertreatment system. Conditions for Running the DiagnosticsThis diagnostic runs continuously when the engine is running. Conditions for Setting the Fault CodesThe ECM detects that the temperature at the SCR catalyst intake is greater than a calibratible value. Action Taken When the Fault Code is Active-The ECM illuminates the amber CHECK...

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. Component values and states from components such as sensors, accelerators, and switches can then 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 DescriptionUnder ordinary operating conditions, the real-time clock in the electronic control module (ECM) is powered by the vehicle’s batteries. If battery power to the ECM is lost, then the real-time clock will be powered by a battery in the engine harness (if equipped). Component LocationThe real-time clock battery is secured to the engine harness near the ECM. Conditions for Running the DiagnosticsThis diagnostic runs continuously when the keyswitch is in the ON position. Conditions for Setting the Fault CodesThe ECM detects that the real-time clock battery voltage is 3.3-VDC. Action Taken When the Fault Code is Active-The ECM flashes...