RING 8S0557 - Caterpillar

The exhaust gas that flows from the exhaust manifold is mixed with fresh air. The NRS meters the mixture of air and exhaust. The NRS also cools the mixture. This mixture will reduce the NOx emissions of the engine.The following NRS consists of the following components:
NRS cooler
NRS venturi
NRS absolute pressure sensor
NRS differential pressure sensor
NRS temperature sensor
NRS valveThe following diagnostic trouble codes aid in detection of pressure and air flow issues within the NRS.Note: Some of the following codes may not be applicable for certain applications.Clear all "Active" codes using Cat ET before proceeding with the following procedure. Refer to Troubleshooting, "Diagnostic Capabilities - Clearing Active Codes for On Board Diagnostics (OBD)" for more information on clearing "Active" codes.Note: The codes that are listed below cannot be cleared from the Cat ET "Logged" screen for 9600 hours after the code becomes logged.
Table 1
Diagnostic Trouble Codes    
CDL Code    J1939 Code    Code Description
(code descriptions may vary)    Comments    
E1090 (2)     3358-16     High EGR Intake Pressure     The ECM detects a higher than desired EGR intake pressure.    
E1095 (1)     2659-17     Low EGR Mass Flow Rate     The ECM detects a lower than desired flow rate through the NRS    
E1096 (1)     2659-15     High EGR Mass Flow Rate     The ECM detects a higher than desired flow rate through the NRS    
E1093 (1)     411-17     Low EGR Differential Pressure     The ECM detects an abnormally low reading from the NRS differential pressure sensor.    
E1094 (1)     411-15     High EGR Differential Pressure     The ECM detects an abnormally high reading from the NRS differential pressure sensor.    Note: EGR is an industry standard 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 SAE, therefore, the diagnostic codes still reflect the EGR nomenclature.
Table 2
Associated Diagnostic Trouble Codes    
E1154    
E1123    
E1092    
3609-17    
3609-18    
5276-7    
412-15    
412-16    
Table 3
Troubleshooting Test Steps    Values    Results    
1. Check for Diagnostic Trouble Codes
A. Establish communication between Caterpillar Electronic Technician (ET) and the ECM. Refer to Troubleshooting, "Electronic Service Tools", if necessary.
B. Troubleshoot any active or logged diagnostic trouble codes before troubleshooting the event codes outlined in this procedure.
Determine if an associated code is active or logged. Table 2 lists associated diagnostic codes.
   
Associated codes    
Result: There are associated codes.
Refer to Troubleshooting, "Event Codes" in order to troubleshoot the associated diagnostic code.
Result: There are no associated codes. If the original diagnostic trouble code was a E1095, E1096, 2659-15 and/or a 2659-17.
Proceed to Test Step 2.
Result: There are no associated codes. If the original diagnostic trouble code was a E1093, E1094, 411-17 and/or 411-15.
Proceed to Test Step 5.
Result: There are no associated codes. If the original diagnostic trouble code was a E1095, E1090, 2659-17 and/or