GASKET 9L1576 - Caterpillar

Use this procedure to troubleshoot a DEF pressure is high. Also, use this procedure if the following event code is active or logged.
Table 1
J1939 Code and Description CDL Code and Description Comments
4334-15
Aftertreatment #1 SCR Dosing Reagent Absolute Pressure : High - least severe (1) E930 (1)
High Aftertreatment #1 DEF Pressure The code is logged.
Dosing is disabled until the pressure is correct.
6875-15
Aftertreatment #1 DEF Dosing Pressure : High - least severe (1) E930 (1)
High Aftertreatment #1 DEF Pressure The code is logged.
Dosing is disabled until the pressure is correct.
Table 2
Associated Codes
J1939 Code CDL Code Troubleshooting Procedure
4334-3 3090-3 Troubleshooting, "Sensor Signal (Analog, Active) - Test"
4334-4 3090-4 Troubleshooting, "Sensor Signal (Analog, Active) - Test"
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"
Illustration 1 g03222281
Diesel Exhaust Fluid (DEF) dosing control cabinet components
Valves are shown in a static state
(1) Dosing control cabinet
(2) DEF line to injector at CEM
(3) Air line to injector at CEM
(4) Compressed air source (customer supplied)
(5) DEF source (customer supplied)
(6) DEF pressure sensor
(7) Air assist pressure sensor
(8) Air pressure regulator
(9) Air assist valve (solenoid)
(10) DEF buffer tank return valve (solenoid)
(11) DEF buffer tank return valve (pneumatic)
(12) DEF buffer tank fill valve (solenoid)
(13) DEF buffer tank fill valve (pneumatic)
(14) DEF level sensor
(15) DEF buffer tank
(16) DEF pumpProbable Causes
Codes
Sensor
DEF injector
DEF line
DEF return valves
DEF pressure
DEF pump wiringRecommended Actions
Table 3
Troubleshooting Test Steps Values Results
1. Check for Codes
A. Turn the 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 present.
Repair: Troubleshoot any associated codes before continuing with this test.
Result: An E930, 4334-15, or 6875-15 code is present.
Proceed to Test Step 2.
2. Check the DEF Pressure Sensor
A. Turn the breaker to the ON position.
B. Connect Cat ET.
C. Monitor Cat ET and record the "Aftertreatment #1 DEF Dosing Pressure".
Pressure
Note: The acceptable range of pressure is 0 20 kPa (0 3 psi).
Result: The recorded pressure is in range.
Proceed to Test Step 3.
Result: The recorded pressure is NOT in range.
Repair: Replace the DEF pressure sensor.
If the problem is not resolved, proceed to Test Step 9.
3. Test the DEF Injector for Plugging
A. Turn the breaker to the ON position.
B. Connect Cat ET.
C. Use Cat ET to activate the following overrides:
- "Aftertreatment #1 Dosing Air Assist Valve Command Override"
D. Monitor the "Aftertreatment #1 DEF Dosing Pressure" in the override screen using Cat ET.
DEF Pressure
Result: The DEF pressure is reading less than 62 kPa (9 psi).
Proceed to Test Step 4.
Result: The DEF pressure reading is between 62 kPa (9 psi) to 255 kPa (37 psi).
Proceed to Test Step 5.
Result The DEF pressure is reading greater than 255