RING-WEAR 7J1731 - Caterpillar

System Operation Description:The NRS is used to introduce a controlled amount of exhaust gas into the intake air supply. The introduction of this inert gas into the combustion air helps to reduce the temperatures and pressures that are created during combustion. The emissions levels of the engine are reduced.The NRS consists of the following components:
Absolute pressure sensor
Cooler
Differential pressure sensor
Temperature sensor
Solenoid for the valve actuator
Valve
VenturiThe following diagnostic trouble codes aid in detection of pressure and air flow issues within the NRS.
Table 1
Diagnostic Trouble Codes
J1939 Code and Description Conditions that Generate the Code System Response
411-15 Engine Exhaust Gas Recirculation Differential Pressure : High - least severe (1) The Electronic Control Module (ECM) detects an abnormally high reading from the NRS differential pressure sensor. The code is logged.
411-17 Engine Exhaust Gas Recirculation Differential Pressure : Low - least severe (1) The ECM detects an abnormally low reading from the NRS differential pressure sensor. The code is logged.
2659-15 Engine Exhaust Gas Recirculation (EGR) Mass Flow Rate : High - least severe (1) The ECM has detected a high flow rate through the NRS. The code is logged.
2659-16 Engine Exhaust Gas Recirculation (EGR) Mass Flow Rate : High - moderate severity (2) The ECM has detected a high flow rate through the NRS. The code is logged.
2659-17 Engine Exhaust Gas Recirculation (EGR) Mass Flow Rate : Low - least severe (1) The ECM has detected a low flow rate through the NRS. The code is logged.
2791-5 Engine Exhaust Gas Recirculation (EGR) Valve Control : Current Below Normal The Electronic Control Module (ECM) detects a low current in the circuit for the NRS actuator solenoid. The code is logged.
2791-6 Engine Exhaust Gas Recirculation (EGR) Valve Control : Current Above Normal The ECM detects a high current in the circuit for the NRS actuator solenoid. The code is logged.
3358-16 Engine Exhaust Gas Recirculation Inlet Pressure : High - moderate severity (2) The ECM detects an abnormally high inlet pressure to the NRS. The code is logged.
Illustration 1 g02138942
Location of the NRS actuator solenoid
Note: Exhaust Gas Recirculation (EGR) is a term used to describe the recirculation of exhaust gas through the engine as a means to reduce NOX emissions. Caterpillar has elected to refer to this system as the NOX Reduction System (NRS). Diagnostic codes are regulated by Society of Automotive Engineers (SAE). The diagnostic codes use the EGR nomenclature.