END BIT (L.H.) 5J6926 - Caterpillar

Use this procedure to troubleshoot a problem with high Diesel Exhaust Fluid (DEF) pressure. Also, use this procedure if the following event code is active or logged.
Table 1
J1939 Code and Description CDL Code and Description Comments
6875-16
Aftertreatment #1 DEF Dosing Pressure : High - moderate severity (2) E930 (2)
High Aftertreatment #1 DEF Pressure The Diesel Exhaust Fluid (DEF) pressure is above the threshold for proper system operation.
DEF dosing is disabled.
Table 2
Associated Codes
J1939 Code CDL Code Troubleshooting Procedure
4335-15 E1969 (1) Troubleshooting, "Air Assist Pressure Is High"
4335-17 E964 (1) Troubleshooting, "Air Assist Pressure Is Low"
4335-18 E964 (2) Troubleshooting, "Air Assist Pressure Is Low"
4335-3 3092-3 Troubleshooting, "Sensor Signal (Analog, Active) - Test"
4335-4 3094-4 Troubleshooting, "Sensor Signal (Analog, Active) - Test"
4376-5 3862-5 Troubleshooting, "Solenoid Valve - Test"
4376-6 3862-6 Troubleshooting, "Solenoid Valve - Test"
6875-3 3090-3 Troubleshooting, "Sensor Signal (Analog, Active) - Test"
6875-4 3090-4 Troubleshooting, "Sensor Signal (Analog, Active) - Test"
7107-5 N/A Troubleshooting, "DEF Pump Motor - Test"
7107-6 N/A Troubleshooting, "DEF Pump Motor - Test"
7107-11 N/A Troubleshooting, "DEF Pump Motor - Test"
7416-5 N/A Troubleshooting, "Solenoid Valve - Test - Aftertreatment"
7416-6 N/A Troubleshooting, "Solenoid Valve - Test - Aftertreatment"
7417-2 N/A Troubleshooting, "DEF Pump Power Supply - Test"
7417-5 N/A Troubleshooting, "Circuit Breaker - Test"
7417-6 N/A Troubleshooting, "Circuit Breaker - Test"
Illustration 1 g03746847
Diesel Exhaust Fluid (DEF) dosing control cabinet components
Valves are shown in a static state
(1) DEF line to injector at CEM
(2) Air line to injector at CEM
(3) Compressed air source (customer supplied)
(4) DEF source (customer supplied)
(5) DEF pressure sensor
(6) Air assist pressure sensor
(7) Air pressure regulator
(8) Air assist valve
(9) DEF buffer tank return valve
(10) DEF buffer tank fill valve
(11) DEF pump
(12) DEF level sensor
(13) DEF buffer tank
Illustration 2 g03747254
Enhanced Troubleshooting Information (ETI) code
Probable Causes
Codes
Sensor
DEF line
DEF injector
DEF pumpRecommended Actions
Table 3
Troubleshooting Test Steps Values Results
1. Check for Codes
A. Turn the DC breaker to the ON position.
B. Connect Cat® Electronic Technician (ET) to the service tool connector.
C. 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: A code is active or logged.
Record the Enhanced Troubleshooting Information (ETI) code with the event. Refer to Illustration 2 for the ETI code location.
Proceed to Test Step 2.
2. Monitor the Catalyst Intake Gas Temperature
A. Turn the DC breaker to the ON position.
B. Connect Cat ET.
C. Use Cat ET to monitor the following temperature:
- "Aftertreatment #1 SCR Catalyst Intake Gas Temperature"
Temperature
Result: The "Aftertreatment #1 SCR Catalyst Intake Gas Temperature" is less than 180° C (356° F)
Proceed to Test Step 3.
Result: The "Aftertreatment #1 SCR Catalyst Intake Gas Temperature" is 180° C (356° F) or higher.
Repair: Use Cat ET to perform the following override:
- Set the "Aftertreatment #1 SCR Dosing Air Assist Valve Command Override" to the OFF position.
Proceed to Test Step 3.
3. Check the DEF Pressure Sensor
A. Turn the DC breaker to the ON position.
B. Connect Cat ET.
C. Use Cat ET to monitor the following pressure:
- "Aftertreatment #1 DEF Dosing Pressure"
Sensor
Result: