COUPLER- 1873546 - 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.
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 Electronic Control Module (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 Cat® 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 E1090 and/or 3358-16.
Proceed to Test Step 3.
Illustration 1 g03781036
Inspection points for the left side of the engine
(1) NRS inlet valve
(2) NRS temperature sensor
(3) NRS outlet valve
Illustration 2 g03781037
Inspection points for the right side of the engine
(4) NRS cooler outlet
(5) NRS cooler inlet
(6) NRS bellows joint
Table 4
Troubleshooting Test Steps Values Results
2. Inspect the NRS for Leakage
A. Inspect the following components of the NRS for leakage:
Exhaust manifold
Connections for NRS cooler inlet and NRS cooler outlet
NRS venturi inlet and outlet connections
Port locations for NRS differential pressure sensor and NRS absolute pressure sensor
Connections for NRS inlet valve and NRS outlet valve
Common signs of a leak in the NRS are loose connections, damaged lines, or components and exhaust soot