PIN 0791917 - Caterpillar

Table 1
Diagnostic Trouble Codes for NOx Conversion Is Low
J1939 Code and Description Pre Conditions for Code Comments
4364-1
Aftertreatment #1 SCR Catalyst Conversion Efficiency : Low - most severe (3) - Engine RPM, MAF data, exhaust temperature, Pre-NOx concentration, estimated reduction efficiency, ambient temperature, atmospheric pressure are within each appropriate range (set value)
- Post-NOx sensors sampling and averaging processes are completed
- No DTC invalidation flag The averaged Post-NOx sensor output is greater than NOx concentration estimated by NOx reduction efficiency for at least 5 minutes Complete the procedure in the order in which the steps are listed.
Table 2
Troubleshooting Test Steps Values Results
1. Determine the Code
A. Establish communication between Caterpillar Electronic Technician (ET) and the DCU. Refer to Troubleshooting, "Electronic Service Tools", if necessary.
B. Are there any other codes associated with the SCR System.
C. If 4364-1 is active ensure NOx sensors are connected correctly.
Pre - NOx Sensor (Black) is on the bottom.
Post - NOx Sensor (Gray) is on the top.
Yes or No
Result: There are codes associated with SCR System
Repair: Troubleshoot those codes first.
Result: There are no other codes associated with the SCR System.
Proceed to Test Step 2.
2. Check the DEF Quality
A. Refer to Systems Operation, Testing and Adjusting, "Diesel Exhaust Fluid Quality - Test" for the correct procedure.
DEF quality standards
Result: DEF is contaminated.
Repair: Replace the DEF Tank Sensor assembly and flush the DEF Tank. Refer to Testing and Adjusting, "Diesel Exhaust Fluid Tank – Flush".
Note: If diesel or oil is confirmed in the DEF, the following DEF components must be replaced: DEF Tank, DEF Heater Unit, DEF Pump, DEF Lines, and DEF Injector.
Result: The DEF is within specification
Proceed to Test Step 3.
3. Inspect All the DEF Lines for Leaks
A. Visually check that the DEF lines are not clogged, leaking, or broken.
Damaged or Clogged
Result: DEF lines are damaged or clogged.
Repair:
- Replace and clean parts as needed.
- Clean the DEF Tank. Refer to Testing and Adjusting, "Diesel Exhaust Fluid Tank – Flush".
- Check the DEF Quality. Refer to Testing and Adjusting, "Diesel Exhaust Fluid Quality – Test".
Result: DEF lines are not damaged nor clogged.
Proceed to Test Step 4.
4. Perform a DEF Dosing System Verification
A. Perform the "DEF Dosing System Verification Test" Which confirms the DEF pump operation.
DEF Pump Operation
Result: The test completed successfully
Proceed to Test Step 5.
Result: The test did not complete successfully.
5. Remove the DEF Injector and Check for Urea Crystals on the DEF Injector Tip
Result: There are no crystals on the tip
Proceed to Test Step 6.
Result: There are urea crystals on the tip.
Repair: Replace the DEF Injector.
6. Test the DEF Injector
A. Test the DEF Injector. Refer to Testing and Adjusting, "Aftertreatment SCR System Dosing – Test".
Dosing Test
Result: DEF injector did not pass dosing test
Repair: Replace the DEF injector.
Result: DEF injector passed dosing test, then contact the Dealer Solution Network (DSN) for further assistance.