3512E Petroleum Engine Caterpillar

Use this procedure to troubleshoot a problem with NOx Reduction System (NRS). Also, use this procedure if one of the following diagnostic codes is active or easily repeated.

Table 1

J1939 Code and Description	CDL Code and Description	Comments
411-15 Engine Exhaust Gas Recirculation Differential Pressure : High - least severe (1)	E1094 (1) High EGR Differential Pressure	The Electronic Control Module (ECM) detects an abnormally high reading from the NOx Reduction System (NRS) differential pressure sensor.
411-17 Engine Exhaust Gas Recirculation Differential Pressure : Low - least severe (1)	E1093 (1) Low EGR Differential Pressure	The ECM detects an abnormally low reading from the NRS differential pressure sensor.
2659-15 Engine Exhaust Gas Recirculation Differential Pressure : High - least severe (1)	E1096 (1) High EGR Mass Flow Rate	The ECM detects a higher than desired flow rate through the NRS.
2659-17 Engine Exhaust Gas Recirculation (EGR) Mass Flow Rate : Low - least severe (1)	E1095 (1) Low EGR Mass Flow Rate	The ECM detects a lower than desired flow rate through the NRS.
3358-16 Engine Exhaust Gas Recirculation Inlet Pressure : High - moderate severity (2)	E1090 (2) High EGR Intake Pressure	The ECM detects the NRS inlet pressure is abnormally high.

Note: Exhaust Gas Recirculation (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 Codes
J1939 Code	CDL Code	Troubleshooting Procedure
411-3	3387-3	Troubleshooting, "Sensor Signal (Analog, Active) - Test"
411-4	3387-4	Troubleshooting, "Sensor Signal (Analog, Active) - Test"
411-13	3387-13	Troubleshooting, "Sensor Calibration Required - Test"
412-3	3386-3	Troubleshooting, "Sensor Signal (Analog, Passive) - Test"
412-4	3386-4	Troubleshooting, "Sensor Signal (Analog, Passive) - Test"
412-15	E1092 (1)	Troubleshooting, "NRS Exhaust Gas Temperature Is High"
412-16	E1092 (2)	Troubleshooting, "NRS Exhaust Gas Temperature Is High"
2791-5	3405-5	Troubleshooting, "Solenoid Valve - Test"
2791-6	3405-6	Troubleshooting, "Solenoid Valve - Test"
3358-3	3385-3	Troubleshooting, "Sensor Signal (Analog, Active) - Test"
3358-4	3385-4	Troubleshooting, "Sensor Signal (Analog, Active) - Test"
3358-13	3385-13	Troubleshooting, "Sensor Calibration Required - Test"
3821-5	3618-5	Troubleshooting, "Solenoid Valve - Test"
3821-6	3618-6	Troubleshooting, "Solenoid Valve - Test"

Illustration 1	g06203940
(1) EGR cooler (2) EGR absolute pressure (3) EGR Delta P (4) EGR valve (5) Venturi (6) Exhaust Restriction Valve (ERV)

Illustration 2	g06210532
(1) EGR cooler (2) EGR absolute pressure (3) EGR Delta P (4) EGR valve (5) Venturi (7) EGR temperature

Table 3

Troubleshooting Test Steps	Values	Results
1. Check the NRS Components for Oil Leaks A. Turn the keyswitch to the OFF position. B. Inspect the following NRS components: - "NOx Reduction System" (NRS) Valve and oil line connections - "Exhaust Restriction Valve" (ERV) and oil line connections	Leaks	Result: No oil leaks were found in the system. Proceed to Test Step 2. Result: Oil leaks were found in the system. Repair: Repair the oil leaks. Proceed to Test Step 2.
2. Check the NRS for Leaks A. Inspect the following NRS components: - 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 valve and ERV valve Note: Common signs of a leak in the NRS are loose connections, damaged lines, or components and exhaust soot buildup around the area that is leaking.	Leaks	Result: No leaks were found in the system. Proceed to Test Step 3. Result: Leaks were found in the system. Repair: Repair the leaks. Proceed to Test Step 3.
3. Check for Codes A. Connect Cat® Electronic Technician (ET) to the service tool connector. B. Look for active codes that are associated with the system for the event code.	Codes	Result: An associated code is active. Repair: Troubleshoot any associated codes before continuing with this test. Result: An E1090, E1095, E1096, 2659-15, 2659-17 or a 3358-16 is active or logged. Proceed to Test Step 4. Result: An E1093, E1094, 411-17 or 411-15 is active or logged. Proceed to Test Step 5.
4. Perform an "EGR System Test" A. Connect Cat ET. B. Use Cat ET to clear all the active diagnostic trouble codes. This action must be done to perform the "EGR System Test". B. Start the engine. C. Use Cat ET to perform the following test: - "EGR System Test"	Test	Result: Error code $1156 "Exhaust Gas Recirculation Differential Pressure Not Responding" is displayed. Proceed to Test Step 5. Result: Error code $1157 "Exhaust Gas Recirculation Intake Pressure Not Responding" is displayed. Proceed to Test Step 6. Result: Error code $116F "Engine Exhaust Gas Recirculation Valve Not Responding to Command" is displayed. Proceed to Test Step 6. Result: Error code $1170 "Engine Exhaust Back Pressure Regulator Not Responding to Command" is displayed. Proceed to Test Step 14. Result: Error code $11C6 "Exhaust Gas Recirculation Differential Pressure Inconsistent" is displayed. Proceed to Test Step 10. Result: Error code $11C7 ""Exhaust Gas Recirculation Differential Pressure Too High" is displayed. Proceed to Test Step 9. Result: Error code $11C8 "Exhaust Gas Recirculation Differential Pressure Too Low" is displayed. Proceed to Test Step 11. Result: Error code $11C9 "Exhaust Gas Recirculation Intake Pressure Too Low" is displayed. Proceed to Test Step 12. Result: The test was successfully. Return to service.
5. Inspect the Mounting Location for the NRS Differential Pressure Sensor A. Turn the keyswitch to the OFF position. B. Refer to Troubleshooting, "Electrical Connectors - Inspect" when checking sensors. C. Ensure that the sensor is installed in the correct orientation. D. Remove the NRS differential pressure sensor. E. Inspect the mounting location for signs of accumulations of soot. The accumulation may indicate further accumulations of soot downstream in the pressure passages.	Soot	Result: Soot build-up is evident in the NRS differential pressure sensor sample ports. Repair: Use hot soapy water and a bore brush to clean out the sample ports. Proceed to Test Step 18. Result: Little or no soot build-up evident. Proceed to Test Step 7.
6. Inspect the NRS Absolute Pressure Sensor and the Mounting Location A. Turn the keyswitch to the OFF position. B. Refer to Troubleshooting, "Electrical Connectors - Inspect" when checking sensors. C. Remove the NRS absolute pressure sensor. D. Visually inspect all the mounting locations for signs of excessive soot. The excessive soot may indicate further buildup downstream in the pressure passages.	Soot	Result: Soot build-up is evident in the absolute pressure sensor sample port. Repair: Use hot soapy water and a bore brush to clean the sample port. Proceed to Test Step 18. Result: Little or no soot build-up evident. Proceed to Test Step 7.
7. Inspect for Swapped Components A. Turn the keyswitch to the OFF position. B. Inspect the electrical connectors that go to the NRS valve actuator and the ERV valve actuator to verify that the connectors are not swapped. C. Inspect the oil supply and drain line installation on the NRS valve are installed correctly and not swapped. Inspect the oil supply and drain line installation on the ERV valve to verify that the lines are installed correctly and not swapped.	Components	Result: The wiring harness connectors are routed to the correct component and the oil supply and drain lines are routed correctly. Proceed to Test Step 8. Result: The wiring harness connectors are NOT routed to the correct component and/or the oil supply and drain lines are NOT routed correctly. Repair: Install the connectors and/or the oil lines to the correct locations. Proceed to Test Step 18.
8. Inspect the NRS Valve A. Turn the keyswitch to the OFF position. B. Remove actuator assembly from NRS valve body. C. Use a straight screwdriver to rotate the valve inside the NRS valve body. The valve should freely rotate from the open to close positions for 90 degrees of rotation.	Valve	Result: NRS valve does not rotate at all, or the valve is difficult to rotate. Repair: Replace the NRS valve body and install the actuator assembly that was previously removed. Proceed to Test Step 18. Result: NRS valve does rotate freely from open to close. Repair: Install new actuator assembly. Proceed to Test Step 18.
9. Inspect the ERV Valve A. Turn the keyswitch to the OFF position. B. Ensure that the oil supply and return lines are connected to the proper location and are not reversed. B. Remove actuator assembly from ERV valve body. C. Use a straight screwdriver to rotate the valve inside the NRS valve body. The valve should freely rotate from the open to close positions for 90 degrees of rotation.	Valve	Result: ERV valve does not rotate at all, or the valve is difficult to rotate. Repair: Replace the NRS valve body and install the actuator assembly that was previously removed. Proceed to Test Step 18. Result: ERV valve does rotate freely from open to close. Repair: Install new actuator assembly. Proceed to Test Step 18.
10. Inspect the Mounting Location for the NRS Differential Pressure Sensor A. Turn the keyswitch to the OFF position. B. Refer to Troubleshooting, "Electrical Connectors - Inspect" when checking sensors. C. Ensure that the sensor is installed in the correct orientation. D. Remove the NRS differential pressure sensor. E. Inspect the mounting location for signs of accumulations of soot. The accumulation may indicate further accumulations of soot downstream in the pressure passages.	Soot	Result: Soot build-up is evident in the NRS differential pressure sensor sample ports. Repair:Use hot soapy water and a bore brush to clean out the sample ports. Proceed to Test Step 18. Result: Little or no soot build-up evident. Proceed to Test Step 18.
11. Inspect the NRS Valve and the ERV Valve Connectors A. Turn the keyswitch to the OFF position. B. Inspect the electrical connectors that go to the NRS valve actuator and the ERV valve actuator to make sure that the connectors are not swapped.	Connectors	Result: The connectors were swapped. Repair: Install the connectors to the correct components. Proceed to Test Step 18.
12. Inspect the NRS Absolute Pressure Sensor and the Mounting Location A. Turn the keyswitch to the OFF position. B. Refer to Troubleshooting, "Electrical Connectors - Inspect" when checking sensors. C. Remove the NRS absolute pressure sensor. D. Visually inspect all the mounting locations for signs of excessive soot. The excessive soot may indicate further buildup downstream in the pressure passages.	Soot	Result: Soot build-up is evident in the absolute pressure sensor sample port. Repair: Use hot soapy water and a bore brush to clean the sample port. Proceed to Test Step 18. Result: Little or no soot build-up evident. Proceed to Test Step 13.
13. Inspect the NRS Cooler for Plugging A. Turn the keyswitch to the OFF position. B. Inspect the NRS coolers for sooting/plugging that could be restricting the exhaust flow through the coolers.	Connectors	Result: The NRS coolers were plugged Repair: Install the connectors to the correct components. Proceed to Test Step 18.
14. Inspect the Mounting Location for the NRS Differential Pressure Sensor A. Turn the keyswitch to the OFF position. B. Refer to Troubleshooting, "Electrical Connectors - Inspect" when checking sensors. C. Ensure that the sensor is installed in the correct orientation. D. Remove the NRS differential pressure sensor. E. Inspect the mounting location for signs of accumulations of soot. The accumulation may indicate further accumulations of soot downstream in the pressure passages.	Soot	Result: Soot build-up is evident in the NRS differential pressure sensor sample ports. Repair: Use hot soapy water and a bore brush to clean out the sample ports. Proceed to Test Step 18. Result: Little or no soot build-up evident. Proceed to Test Step 15.
15. Inspect the NRS Absolute Pressure Sensor and the Mounting Location A. Turn the keyswitch to the OFF position. B. Refer to Troubleshooting, "Electrical Connectors - Inspect" when checking sensors. C. Remove the NRS absolute pressure sensor. D. Visually inspect all the mounting locations for signs of excessive soot. The excessive soot may indicate further buildup downstream in the pressure passages.	Soot	Result: Soot build-up is evident in the absolute pressure sensor sample port. Repair: Use hot soapy water and a bore brush to clean the sample port. Proceed to Test Step 18. Result: Little or no soot build-up evident. Proceed to Test Step 16.
16. Inspect the NRS Valve and the ERV Valve Connectors A. Turn the keyswitch to the OFF position. B. Inspect the electrical connectors that go to the NRS valve actuator and the ERV valve actuator to verify that the connectors are not swapped.	Connectors	Result: The connectors were connected to the correct components. Proceed to Test Step 17. Result: The connectors were swapped. Repair: Install the connectors to the correct components. Proceed to Test Step 18.
17. Inspect the ERV Valve A. Turn the keyswitch to the OFF position. B. Ensure that the oil supply and return lines are connected to the proper location and are not reversed. C. Remove actuator assembly from ERV valve body. D. Use a straight screwdriver to rotate the valve inside the ERV valve body. The valve should freely rotate from the open to close positions for 90 degrees of rotation.	Valve	Result: ERV valve does not rotate at all, or the valve is difficult to rotate. Repair: Replace the NRS valve body and install the actuator assembly that was previously removed. Proceed to Test Step 18. Result: ERV valve does rotate freely from open to close. Repair: Install new actuator assembly. Proceed to Test Step 18.
18. Perform an "EGR System Test". A. Connect Cat ET. B. Use Cat ET to clear all the active diagnostic trouble codes. This action must be done to perform the "EGR System Test". B. Start the engine. C. Use Cat ET to perform the following test: - "EGR System Test"	Test	Result: The test was successfully. Return to service. Result: The test was not successfully. Review the results on Test Step 4. Proceed to the appropriate step based off the error message.

If the procedure did not correct the issue, contact your Cat dealer Technical Communicator (TC). For further assistance, your TC can confer with the Dealer Solutions Network (DSN).