18955M Mariner SHIM (0.12MM) SEE NOTE #3

Table 1
J1939 Code and Description CDL Code and Description Comments
6875-18
Aftertreatment #1 DEF Dosing Pressure : Low - least severe (1) E931 (1)
Low Aftertreatment #1 DEF Pressure The Diesel Exhaust Fluid (DEF) pressure is below 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"
Illustration 1 g03747254
Enhanced Troubleshooting Information (ETI) code
Illustration 2 g06305577
DEF Component Locations
(1) DEF Injector Nozzle
(2) DEF Inlet Line Connection
(3) DEF Pump
(4) DEF Pressure SensorProbable Causes
Codes
Gas temperature
Sensor
Leaks
DEF line
Voltage
LED light
DEF pump
DebrisRecommended Actions
Table 3
Troubleshooting Test Steps Values Results
1. Check for Codes
A. Apply DC power to the engine and aftertreatment system.
B. Connect Cat® Electronic Technician (Cat ET) Service Tool 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 1 for the ETI code location.
Proceed to Test Step 2.
2. Monitor the Catalyst Intake Gas Temperature
A. Apply DC power to the engine and aftertreatment system.
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:
1. Set the "Aftertreatment #1 SCR Dosing Air Assist Valve Command Override" to OFF.
Proceed to Test Step 3.
3. Check the Diesel Exhaust Fluid (DEF) Pressure Sensor
A. Apply DC power to the engine and aftertreatment system.
B. Connect Cat ET.
C. Use Cat ET to monitor the following pressure:
- "Aftertreatment #1 DEF Dosing Pressure"
Sensor
Result: The DEF pressure sensor reads 0 20 kPa (0 3 psi).
Proceed to Test Step 4.
Result: The DEF pressure sensor does not read 0 20 kPa (0 3 psi).
Repair: Replace the DEF pressure sensor.
Proceed to Test Step 14.
4. Inspect for DEF and Air Leaks
A. Remove DC power from the engine and aftertreatment system.
B. Inspect the DEF lines between the remote DEF supply and the dosing cabinet.
C. Inspect the lines and manifold inside the dosing cabinet.
D. Inspect the DEF lines between the dosing cabinet and the DEF injector.
E. Inspect the air lines for signs of leakage and ensure that lines are connected.
DEF and Air Leaks
Result: There were no DEF or air leaks.
Proceed to Test Step 5.
Result: There were DEF and/or air leaks.
Repair: Repair or replace damaged components.
Proceed to Test Step 14.
5. Determine the ETI Code
A. Use the ETI code recorded in Step 1 to determine the troubleshooting.
Note: If an ETI code cannot be determined, complete all the steps.
Code
Result: An ETI code of 1 is present.
Proceed to Test Step 6.
Result: An ETI code of 3 is present.
Proceed to Test Step 7.
Result: An ETI code of 4 is present. A failed DEF return valve has been detected.
Repair: Replace the DEF return valve.
Proceed to Test Step 14.
6. Inspect the DEF/Air Pressure Line
A. Remove DC power from the engine and aftertreatment system.
B. Disconnect the DEF pressure line from the dosing cabinet.
C. Disconnect the DEF pressure line from the DEF injector.
D. Pour warm water through the DEF pressure line and verify that the line is not blocked.
DEF Line
Result: The DEF/Air pressure line is blocked.
Repair: Clean the DEF/Air pressure line.
Proceed to Test Step 14.
Result: The DEF/Air pressure line is not blocked. A blocked DEF injector has been detected.
Repair: Clean or replace the DEF injector.
Proceed to Test Step 14.
7. Check for adequate DEF supply to the dosing cabinet from the OEM.
DEF Supply
Result: The DEF supply to the dosing cab