C27 and C32 Engines for Caterpillar Built Machines Caterpillar

Use this procedure in order to troubleshoot a high differential pressure for the air inlet system. Also, use this procedure if one of the following event codes are active. Refer to Troubleshooting, "Event Codes" for information about event codes. Access the engine monitoring system on Caterpillar Electronic Technician (ET) in order to view the current trip points for these codes. For information on the engine monitoring system, refer to Troubleshooting, "Engine Monitoring System".

Table 1

CDL Code and Description	Conditions which Generate the Code	System Response
E1092(1) High Engine Exhaust Gas Recirculation Temperature	The temperature of the exhaust gas in the "NOx" Reduction System (NRS) actuator has exceeded the threshold for the programmed delay time.	The code is logged.
E1092(2) High Engine Exhaust Gas Recirculation Temperature

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 NO_X Reduction System (NRS). Diagnostic codes are regulated by SAE. The diagnostic codes will reflect the EGR nomenclature.

Illustration 1	g02128173
Location of the NRS components (top side engine view) (1) NRS valve (2) NRS temperature sensor

Illustration 2	g02128654
Location of the components for the NRS cooler that is on the left side of the engine (left side engine view) (3) Vent line (4) Coolant inlet tube (5) Piping for the exhaust inlet (6) NRS cooler (7) Coolant outlet tube (8) Exhaust outlet piping (7) Coolant outlet

Table 2

Associated Codes
CDL Code	WCI
E361	(1), (2), or (3)
E1095	(2)

Table 3

Troubleshooting Test Steps	Values	Results
1. 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: No associated codes are active at this time. The E1092 remains active. Proceed to Test Step 2. Result: The E361 code is active at this time. Repair: The associated code may be indicating an overheating condition for the engine. Verify that the repair eliminated the problem. Result: The E1092 code is accompanied by the E1095 code. Repair: There may be a problem with the NRS cooler. Proceed to Test Step 3.
2. Use Cat ET to perform an "EGR Service Test" A. Clear all logged codes. Use Cat ET to perform an "EGR Service Test". a. Select the "Diagnostics" drop-down menu. b. Select the "Diagnostics Tests" from the menu. c. Select the "EGR Service Test". B. Once "EGR Service Test" is selected, follow the instructions on the display screen in order to run the test.	EGR Service Test	Result: The "EGR Service Test" is successful. There may be a problem with the NRS cooler. Proceed to Test Step 3. Result: The "EGR Service Test" is not successful due to an E1092 code that is active. Repair: The NRS system appears to be overheating. Check the condition of the vent lines for the coolers to the inlet into the engine block. If necessary, replace the vent lines from the cooler to the engine block. Remove the exhaust lines from the inlet and the outlet of the coolers. Inspect the internal passage of the coolers for indications of coolant leakage. If evidence of coolant leakage is found, replace the coolers. Clear all logged codes. Use Cat ET to perform an "EGR Service Test" in order to verify that the problem is resolved. Verify that the repair eliminated the problem.
3. Perform a Leak Test on the NRS Coolers A. Remove the NRS coolers from the engine. Refer to Disassembly and Assembly for more information. B. Perform a leak test on each of the coolers. Refer to the Testing and Adjusting manual for the proper procedure.	NRS Leak Test	Result: The coolers are not leaking internally. Repair: Clean the coolers. Refer to the Testing and Adjusting manual for the proper procedure that is used to clean the NRS cooler. If the problem is not resolved, contact your Technical Communicator (TC) for further instructions. Result: The coolers are leaking internally. Repair: Replace the coolers. Replace the exhaust bellows at the inlet and the outlet of the cooler. Clear all diagnostic codes. Use Cat ET to perform an "EGR Service Test" in order to verify that the problem is resolved. Verify that the repair eliminated the problem.