C13 Industrial Engine Caterpillar

The ECM is monitoring the NOx level being reported by the sensor. If the NOx value is not steady when the engine speed/fueling is steady, the codes listed below will log. If the NOx value is steady when the engine speed/load is changing, the codes listed below will log.

Table 1 lists the diagnostic codes for the NOx sensors.

Table 1

Diagnostic Trouble Codes
J1939 Code and Description	Comments
3216-7 Aftertreatment #1 Intake NOx : Not Responding Properly	The aftertreatment intake NOx level is not responding as expected. The code is logged.
3226-7 Aftertreatment #1 Outlet NOx : Not Responding Properly	The aftertreatment outlet NOx level is not responding as expected. The code is logged.

Table 2

Required Tools
Qty	Part Number	Part Description
1	431-7087	Tool Gp
1	441-0451	Tool Gp

Reference: Refer to the Disassembly and Assembly for the appropriate procedure for the removal and installation of components.

Table 3

Troubleshooting Test Steps	Values	Results
1. Check the Diesel Exhaust Fluid (DEF) Quality. A. Measure the DEF quality. Refer to Testing and Adjusting, "Diesel Exhaust Fluid Quality - Test" for the correct procedure.	DEF Quality	Result : The DEF is not contaminated and the concentration is not within the acceptable range. Repair : Drain the DEF from the tank. Refill the tank with DEF that meets ISO 22241 quality standards. Proceed to Test Step 3. Result : The DEF is not contaminated and the concentration is within the acceptable range. Proceed to Test Step 2. Result : The DEF is contaminated. Repair : Contact the Dealer Solution Network (DSN) for further information.
2. Perform the "DEF Dosing System Accuracy Test" Using Cat® Electronic Technician (ET) A. Refer to Testing and Adjusting, Aftertreatment SCR System Dosing Test, for the correct procedure.	DEF Dosing System Accuracy Test	Result : The quantity collected is within specifications. Repair : Install the DEF injector. Proceed to Test Step 4. Result : The quantity collected is below specification. Proceed to Test Step 3. Result : The quantity collected is above specification. A failed DEF injector has been detected. Repair : Replace the failed DEF injector. Proceed to Test Step 4.
3. Check the DEF Pressure Line. A. Turn the keyswitch to OFF. Allow 2 minutes to elapse before proceeding. B. Visually inspect the lines for leaks or damage. C. Remove the DEF pressure line between the DEF pump and the DEF injector. D. Inspect the DEF pressure line for obstructions. Flush the line with water or low-pressure air, if necessary. Note: Possible obstructions are ice, DEF deposits, or debris.	Restrictions, Obstructions, or Leaks	Result : An obstruction was found. Repair : Flush or replace the line. Install the DEF injector. Proceed to Test Step 4. Result : An obstruction was not found. Repair : Proceed to Troubleshooting, "DEF Pressure is Low".
4. Perform an "Aftertreatment System Functional Test" A. Establish communication between Cat ET and the engine Electronic Control Module (ECM). B. Perform a "Aftertreatment System Functional Test" using Cat ET.	Successful Test	Result : The test completed successfully. Return the unit to service. Result : The test did not complete successfully. Proceed to Test Step 5.
5. Check for an Engine Misfire A. Establish communication between Cat ET and the engine ECM. B. Perform a "Cylinder Cutout Test".	Misfire	Result : A misfire was detected. Repair : Replace or repair the failed component or components. Proceed to Test Step 7. Result : A misfire was not detected. Proceed to Test Step 6.
6. Check the Exhaust System for Leaks A. Check the entire exhaust system for leaks.	Exhaust Leaks	Result: There were not any exhaust leaks found. Repair : For a 3216-7 or E1431 (2) code replace the intake NOx sensor. Repair : For a 3226-7 or E1432 (2) code replace the outlet NOx sensor. Proceed to Test Step 7. Result : There were exhaust leaks found. Repair : Repair the exhaust leaks. Proceed to Test Step 7.
7. Perform the "Aftertreatment System Functional Test" in Cat ET A. Establish communication between Cat ET and the engine ECM. B. Perform the "Aftertreatment System Functional Test".	Successful Test	Result: The test completed successfully. Return the unit to service.