Selective Catalytic Reduction Retrofit Aftertreatment General Information Caterpillar


General Information
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Selective Catalytic Reduction Retrofit Aftertreatment [UENR4333]
ENGINE ARRANGEMENT
ENGINE AR
Selective Catalytic Reduction Retrofit Aftertreatment General Information
1.1. Status Codes
2.1. Exhaust Temperature Is Low
3.2. Probable Causes
4.2. Recommended Actions
5.1. High Diesel Exhaust Fluid Outlet Pressure
6.2. Probable Causes
7.2. Recommended Actions
8.1. Increased Exhaust Backpressure
9.2. Probable Causes
10.2. Recommended Actions
11.1. Internal Electrical Failures
12.2. Probable Causes
13.2. Recommended Actions
14.1. Low Air Pressure
15.2. Probable Causes
16.2. Recommended Actions
17.1. Low Diesel Exhaust Fluid Supply Pressure
18.2. Probable Causes
19.2. Recommended Actions
20.1. Solenoids Are Not Functioning
21.2. Probable Causes
22.2. Recommended Actions

Status Codes

The following status codes identified a problem with a particular sensor. If the sensor is out of range, the system defaults to an Open loop condition where dosing pump flow is based upon turbo boost pressure.

The following status codes with associated fault light will continue until the sensor error is corrected:

  • Currently running in Open Loop (OL) mode. No connection to Pre NOx sensor: The system senses the Pre NOx sensor has been disconnected. Unit is in OL mode.

  • Currently running in OL mode. Pre NOx sensor not at temperature: The system senses the heater in the Pre NOx sensor has not the reached the proper operating condition. Unit is in OL mode.

  • Currently running in OL mode. Pre NOx sensor signal not valid: The reading from the Pre NOx sensor is no valid. Unit is in OL mode.

  • Currently running in OL mode. No connection to post NOx sensor: The system senses the Post NOx sensor has been disconnected. Unit is in OL mode.

  • Currently running in OL mode. Post NOx sensor not at temperature: The system senses the heater in the Post NOx sensor has not the reached the proper operating condition. Unit is in OL mode.

  • Currently running in OL mode. Post NOx sensor signal not valid: The reading from the Post NOx sensor is no good. Unit is in OL mode.

The following status codes with no associated fault light will continue until the sensor error is corrected:

  • Exhaust Thermocouple Fault: Check Connections: The controller is not receiving a proper signal from the exhaust temperature thermocouple. Check the wiring for integrity.

  • Boost Thermocouple Fault: Check Connections: The controller is not receiving a proper signal from the exhaust temperature thermocouple. Check the wiring for integrity.

  • 12V Supply Fault: Voltage is at 12V ± 1: The 12V driver, that supplies voltage to the air and purge solenoids, in the controller is not receiving proper voltage.

  • 5V Supply Fault: Voltage is at 5V ± 1: The 5V driver, that supplies voltage to the pressure sensors, in the controller is not receiving proper voltage.

To view a history of the systems status modes, refer to the Systems Operation, "Webpage Interface" for more details.

Exhaust Temperature Is Low

Probable Causes

  • Engine load

  • Exhaust temperature sensors

  • Inlet air temperature

  • Insulation

  • Heater

Recommended Actions

Note: The procedures have been listed in order of probability. Complete the procedures in the order of the listed test steps.

Table 1
Troubleshooting Test Steps     Values     Results    

1. Verify that the Engine Exhaust Temperature is Greater Than or Equal to 300° C (572° F)
   

Engine exhaust temperature
   

Result: The engine exhaust temperature is greater than or equal to
300° C (572° F).

Proceed to Test Step 2.

Result: The engine exhaust temperature is not greater than or equal to
300° C (572° F).

Proceed to Test Step 5.
   

2. Verify that the Engine Inlet Air Temperature is Greater Than or Equal to
0° C (32° F)
.

Note: Measure the inlet air temperature at the air inlet filter.
   

Leak
   

Result: The inlet air temperature is greater than or equal to
0° C (32° F).

Proceed to Test Step 3.

Result: The inlet air temperature is not greater than or equal to
0° C (32° F).

Proceed to Test Step 4.
   

3. Make Sure the Proper Insulation is Installed
   

Proper insulation
   

Result: The proper insulation is installed.

Proceed to Test Step 4.

Result: The proper insulation is not installed.

Repair: Verify with the Application and Installation Guide and the sales engineer for the correct insulation material specifications.
Verify that the repair eliminates the problem.

   

4. Check the Unit for Heaters

Note: Heaters and proper insulation help keep the inlet air temperature at the recommended level.
   

Heaters
   

Result: There are unit heaters.

Repair: Repair or replace heaters as needed.
Verify that the repair eliminates the problem.

Result: There are not unit heaters.

Repair: Install heaters on the unit.
Verify that the repair eliminates the problem.
   

5. Make Sure the Engine Load is Greater Than Boost Pressure Low Limit

A. Verify boost pressure sensor reading with Cat ET.
   

Boost Pressure Low Limit
   

Result: The engine load is greater than Boost Pressure Low Limit.

Proceed to Test Step 6.

Result: The engine load is not greater than Boost Pressure Low Limit.

Repair: Take the engine load greater than Boost Pressure Low Limit.
Verify that the repair eliminates the problem.
   

6. Check the Exhaust Temperature Sensors

Note: The exhaust temperature sensors fail open at
1260° C (2300° F).    

Exhaust temperature sensors
   

Result: The exhaust temperature sensors are OK.

Verify the engine performing as expected.

Result: The exhaust temperature sensors are Not OK.

Repair: Repair or replace the suspected exhaust temperature sensor.
Verify that the repair eliminates the problem.
   

High Diesel Exhaust Fluid Outlet Pressure

Note: High Diesel Exhaust Fluid (DEF) outlet pressure usually occurs at pressures greater than 827 kPa (120 psi) and the pressure gauge shows a pressure spike.

Probable Causes

  • Crystallized DEF

  • Damaged injector assembly

  • Plugged injector assembly

Recommended Actions

Note: The procedures have been listed in order of probability. Complete the procedures in the order of the listed test steps.

Table 2
Troubleshooting Test Steps     Values     Results    

1. Inspect the DEF Lines from the Dosing Cabinet to the Injector Assembly
   

Lines
   

Result: The DEF lines from the dosing cabinet to the injector assembly are OK.

Proceed to Test Step 2.

Result: The DEF lines from the dosing cabinet to the injector assembly are NOT OK.

Repair: Repair or replace the DEF lines as needed.
Verify that the repair eliminates the problem.
   

2. Inspect the Injector Nozzle.
   

Injector nozzle
   

Result: The injector nozzle is OK.

Proceed to Test Step 3.

Result: The injector nozzle is NOT OK.

Repair: Repair or replace the injector nozzle as needed.
Verify that the repair eliminates the problem.
   

3. Inspect the Injector Assembly
   
Injector assembly    
Result: The injector assembly is OK.

Proceed to Test Step 4.

Result: The injector assembly is NOT OK.

Repair: Repair or replace the injector assembly as needed.
Verify that the repair eliminates the problem.
   

4. Verify the Gauge is Working Properly.
   
Gauge    
Result: The gauge is OK.

STOP

Result: The gauge is NOT OK.

Repair: Repair or replace the injector assembly as needed.
Verify that the repair eliminates the problem.
   

Increased Exhaust Backpressure

Probable Causes

  • Exhaust leaks

  • Increased back pressure

  • Increased Diesel Exhaust Fluid (DEF)

  • Sensor failure

Recommended Actions

Note: The procedures have been listed in order of probability. Complete the procedures in the order of the listed test steps.

Table 3
Troubleshooting Test Steps     Values     Results    

1. Unit is Experiencing Increase DEF Usage

A. Check the DEF usage.
   

DEF usage
   

Result: The unit is using more DEF.

Proceed to Test Step 2.

Result: The unit is not using more DEF.

Proceed to Test Step 3.
   

2. Measure the Back Pressure and Compare the Data with the Baseline Data.

Note: The baseline data is the Commissioning Report.

A. Measure the back pressure with a manometer.
   

Back pressure
   

Result: The back pressure is greater than or equal to
12.70 cm of H2O (5 inch of H2O).

Repair: Calibrate the exhaust pressure sensor. Refer to Systems Operation / Testing and Adjusting, UENR4332, "Setting Offset and Multiplier on 5V Pressure Sensors" for more information.
Verify that the repair eliminates the problem.

If calibrating the exhaust pressure sensor did not fix the problem, proceed to Test Step 4.

Result: The back pressure is not greater than or equal to
12.70 cm of H2O (5 inch of H2O).

Proceed to Test Step 3.
   

3. Inspect Selective Catalyst Reduction (SCR) Unit

A. Check the SCR unit for exhaust leaks or exhaust gases.

B. Check the SCR unit for defective welds.

C. Check the SCR unit for broken bellows.

D. Check the SCR unit for cracked hatch flange gaskets.
   
Leaks, broken weld, broken bellows, and cracked hatch flange gaskets    
Result: There are exhaust leaks or exhaust gases.

Repair: Repair or replace the exhaust as needed.
Verify that the repair eliminates the problem.

Result: There are not any exhaust leaks or exhaust gases.

Result: There are broken welds.

Repair: Repair or replace the broken welds as needed.
Verify that the repair eliminates the problem.

Result: There are not any broken welds.

Result: There are broken bellows.

Repair: Repair or replace the broken bellows as needed.
Verify that the repair eliminates the problem.

Result: There are not any broken bellows.

Result: There are cracked hatch flange gaskets.

Repair: Repair or replace the cracked hatch flange gaskets as needed.
Verify that the repair eliminates the problem.

Result: There are not any cracked hatch flange gaskets.

If you have a SCR and a Diesel Particulate Filter (DPF), proceed to Test Step 4.

If you have a SCR and a Diesel Oxidation Catalyst (DOC), proceed to Test Step 5.
   

4. Check the DPF for Contamination

A. Inspect the DPF or SCR for soot.
   
Soot or insulation material    
Result: There is soot on the DPF.

Repair: Ensure the cell depth measures
285.75 mm (11.25 inch).
If the cell depth does not measure
285.75 mm (11.25 inch), the cell needs to be cleaned. Refer to Systems Operation / Testing and Adjusting, UENR4332, "Cleaning the Diesel Particulate Filter" for more information.
If cleaning the cell does not fix the cell depth specification, replace the DPF.

Verify that the repair eliminates the problem.

Result: There is not any soot on the DPF.

STOP

Result: There is debris or insulation material on the DPF.

Repair: Cover the source of debris or insulation material with stainless steel.
Verify that the repair eliminates the problem.


Result: There is not any debris or insulation material on the DPF

STOP
   

5. Check the DOC and SCR for Contamination

A. Inspect the open cells with a flashlight.
   

Cell plugged
   

Result: The open cells are plugged.

Repair: Clean the cells.
Note: Do not use high-pressure air to clean of the DOC or SCR.
If the leading edge of the cells are covered with insulation fiber or soot, vacuum off the affected area.
If cleaning the cells does not unplug the cells, replace the DOC.
If the cells are contaminated, replace the DOC or SCR.
Verify that the repair eliminates the problem.

Result: The open cells are not plugged.

STOP
   

6. Check the Engine for Failure

A. Inspect the engine for coolant, oil, and debris.
   
Coolant, oil, and debris.    
Result: The engine is OK.

Proceed to Test Step 7.

Result: The engine is NOT OK.

Repair: Repair or replace the failed parts.
Verify that the repair eliminates the problem.
   

7. Inspect SCR System for Failure or Contamination
   
Source of failure or contamination    
Result: Determined the source of failure or contamination.

Repair: Repair the cause of failure or contamination.
Contact your Cat dealer Technical Communicator (TC) to determine appropriate cleaning method for failure.

Result: The source of failure or contamination was not determined .

Contact your Cat dealer Technical Communicator (TC).
   

Internal Electrical Failures

Probable Causes

  • Cable connections

  • ECM fan

  • Ethernet switch

  • Fuses and breakers

  • Network configurations

  • Power supply

  • Sensors

Recommended Actions

Note: The procedures have been listed in order of probability. Complete the procedures in the order of the listed test steps.

Table 4
Troubleshooting Test Steps     Values     Results    

1. Verify the NOx, Temperature, and Pressure Sensors Are Working
   

Sensors
   

Result: The NOx, temperature, and pressure sensors are working.

Proceed to Test Step 2.

Result: The NOx, temperature, and pressure sensors are not working.

Repair: Repair or replace the suspect sensor as needed.
Verify that the repair eliminates the problem.
   

2. Verify the Touch Monitor Display loads the Webpage
   

Normal operation
   

Result: The touch monitor display loads webpage.

Proceed to Test Step 3.

Result: The touch monitor display does not load webpage.

Repair: Repair or replace as needed.
Verify that the repair eliminates the problem.
   

3. Check the Cumulative DEF Field for Counting
   
Counting    
Result: The cumulative DEF field is counting.

Proceed to Test Step 4.

Result: The cumulative DEF field is not counting.

Proceed to Test Step 7.
   

4. Check the Supply Voltage to the Cabinet

Note: The power supply is site specific.
   

90V to 240V
   

Result: 90V to 240V is supplied to the cabinet.

Proceed to Test Step 5.

Result: 90V to 240V is not supplied to the cabinet.

Repair: Repair or replace the power supply as needed.
Verify that the repair eliminates the problem.
   

5. Check the Voltage to the Power Supply Inside the Cabinet
   

24V
   

Result: 24V is supplied inside the cabinet.

Proceed to Test Step 6.

Result: 24V is not supplied inside the cabinet.

Repair: Repair or replace the 24V Power Supply Inside the Cabinet as needed.
Verify that the repair eliminates the problem.
   

6. Check the Fuses and Breakers
   

Fuses and breakers
   

Result: The fuses and breakers are good.

Proceed to Test Step 11.

Result: The fuses and breakers are not good.

Repair: Repair or replace the fuses and breakers as needed.
Verify that the repair eliminates the problem.
   

7. Verify that the ECM Fan is Working Properly
   

Fan
   

Result: The ECM fan is working properly.

Proceed to Test Step 8.

Result: The ECM fan is not working properly.

Repair: Repair or replace the ECM fan as needed.
Verify that the repair eliminates the problem.
   

8. Check the Ethernet Switch
   

Ethernet switch
   

Result: The ethernet switch is working.

Proceed to Test Step 9.

Result: The ethernet switch is not working.

Repair: Repair or replace the ethernet switch as needed.
Verify that the repair eliminates the problem.
   

9. Verify that the 40 Pin Connector is Seated in the ECM
   

40 Pin connector seated
   

Result: The 40 pin connector is seated in the ECM.

Proceed to Test Step 10.

Result: The 40 pin connector is not seated in the ECM.

Repair: Repair or replace the 40 pin connector as needed.
Verify that the repair eliminates the problem.
   

10. Verify that the Network Cable is Properly Connected
   

AVS5 cable
   

Result: The network cable is properly connected.

Proceed to Test Step 11.

Result: The network cable is not properly connected.

Repair: Repair or replace the network cable as needed.
Verify that the repair eliminates the problem.
   

11. Reboot the System

A. Flash the ECM with new software.

B. Reboot the system again.
   

Problem continues
   

Result: The system is working properly.

STOP

Result: The system is not working properly.

Repair: Reflash the ECM with new software.
Verify that the repair eliminates the problem.

Result: The system is working properly.

STOP.

Result: The system is not working properly.

Proceed to Test Step 12.
   

12. Check TCP / IP or Subnet Mask Configuration
   

Configured
   

Result: The TCP/IP or Subnet mask is configured correctly.

STOP

Result: The TCP/IP or Subnet mask is not configured correctly.

Repair: Configure the webpage and the VPN network to the touch monitor. The webpage and the VPN network are similar to the commissioning steps. Refer to Systems Operation / Testing and Adjusting, UENR4332, "Touch Monitor - Setup" for more information.
Verify that the repair eliminates the problem.

If the problem continues, replace the ECM and the input commissioning settings.
   

Low Air Pressure

Probable Causes

  • Air compressor

  • Air lines

  • Air pressure switch

  • Air regulator

  • Air solenoid

  • Plugged injector nozzle

Recommended Actions

Note: The acceptable Delta P across the air inlet regulator and the outlet air pressure is 103 ± 34 kPa (15 ± 5 psi) with the air regulator set at 483 kPa (70 psi).

Note: The procedures have been listed in order of probability. Complete the procedures in the order of the listed test steps.

Table 5
Troubleshooting Test Steps     Values     Results    

1. Check the Air Flow through the Air Solenoid

Note: Remove the air line from the dosing cabinet to injector assembly before servicing the air solenoid.

A. Check the air flow through the air solenoid.

B. Inspect the air lines from the dosing cabinet to the injector assembly.
   

Air flow
   

Result: The air flow through the air solenoid is OK.

Proceed to Test Step 3.

Result: The air flow through the air solenoid is NOT OK.

Repair: Repair or replace the air solenoid as needed.
Verify that the repair eliminates the problem.

Result: The air lines are OK.

Proceed to Test Step 3.

Result: The air lines are NOT OK.

Repair: Repair or replace the airlines from the dosing cabinet to injector assembly as needed.
Verify that the repair eliminates the problem.
   

2. Verify the Air Pressure Regulator Maintains Pressure
483 kPa (70 psi)
.
   


483 kPa (70 psi)
   

Result: The air pressure regulator maintains
483 kPa (70 psi).

Proceed to Test Step 3.

Result: The air pressure regulator does not maintains
483 kPa (70 psi).

Proceed to Test Step 4.
   

3. Check the Diesel Exhaust Fluid (DEF) Outlet Pressure Gauge for No Pulsation

Note: A
69 to 138 kPa (10 to 20 psi) pulsation will show on the pressure gauges during normal dosing.

Note: If the air-side of the injector nozzle is plugged, low pressure in the DEF circuit is created. The low-pressure results in a DEF outlet pressure gauge with no pulsation.
   

290 ± 14 kPa (42 ± 2 psi)    

Result: The DEF outlet pressure gauge reads
290 ± 14 kPa (42 ± 2 psi).

Proceed to Test Step 4.

Result: The DEF outlet pressure gauge does not read
290 ± 14 kPa (42 ± 2 psi).

Repair: Repair or replace the injector nozzle or injector assembly as needed.
Verify that the repair eliminates the problem.
   

4. Check the Air Supply from the Air Compressor


689 ± 138 kPa (100 ± 20 psi)    


689 ± 138 kPa (100 ± 20 psi) at 10 cfm
   

Result: The supply pressure is
689 ± 138 kPa (100 ± 20 psi) at 10 cfm.

Proceed to Test Step 5.

Result: The supply pressure is not
689 ± 138 kPa (100 ± 20 psi) at 10 cfm.

Repair: Repair or replace the air supply lines to the dosing cabinet or the air compressor as needed.
Verify that the repair eliminates the problem.
   

5. Verify that the Air Pressure Switch is Working

Note: The air pressure switch is set at
276 ± 7 kPa (40 ± 1 psi).

Refer to Systems Operation / Testing and Adjusting, REHS8213, "Air Pressure Switch" for more information.
   

Pressure switch
   

Result: The air pressure switch is working.

STOP

Result: The air pressure switch is not working.

Repair: Repair or replace the air pressure switch.
Verify that the repair eliminates the problem.
   

Low Diesel Exhaust Fluid Supply Pressure

Note: No visible pulsation at the Diesel Exhaust Fluid (DEF) pressure gauge.

Probable Causes

  • Air in the system

  • Debris and contamination

  • DEF tank level

  • Pump size

  • Supply and dosing pumps

Recommended Actions

Note: The procedures have been listed in order of probability. Complete the procedures in the order of the listed test steps.

Table 6
Troubleshooting Test Steps     Values     Results    

1. Check the DEF Tank for the Proper Level
   

Tank level
   

Result: The DEF tank has the proper level.

Proceed to Test Step 2.

Result: The DEF tank does not have the proper level.

Repair: Fill the DEF tank as needed.
Verify that the repair eliminates the problem.
   

2. Check the DEF Supply Pump for Normal Operation.
   

Normal pump operation
   

Result: The DEF supply pump is operating correctly.

Proceed to Test Step 3.

Result: The DEF supply pump is not operating correctly.

Repair: Repair or replace the DEF supply pump as needed.
Verify that the repair eliminates the problem.
   

3. Verify that the DEF Supply Pump is the Correct Size for the Unit
   
Correct size of pump    
Result: The DEF supply pump is the correct size.

Proceed to Test Step 4.

Result: The DEF supply pump is not the correct size.

Repair: Repair or replace the DEF supply pump as needed.
Verify that the repair eliminates the problem.

   

4. Inspect the DEF Supply and Outlet Lines for Visible Cracks
   

Cracks
   

Result: The DEF supply and outlet lines are cracked.

Repair: Repair or replace the air supply lines to the dosing cabinet as needed.
Verify that the repair eliminates the problem.

Result: The DEF supply and outlet lines are not cracked.

Proceed to Test Step 5.
   

5. Inspect the DEF Supply and Outlet Lines for Debris and Contamination

A. Remove the DEF supply lines from the inlet of the cabinet.

B. Inspect the DEF supply and outlet lines for debris and contamination.
   
Debris or Contamination    
Result: The DEF supply and outlet lines have debris or contamination.

Repair: Repair or replace the DEF supply and outlet lines as needed.
Verify that the repair eliminates the problem.

Result: The DEF supply and outlet lines do not have any debris or contamination.

Proceed to Test Step 6.
   

6. Check the Y-sediment Strainer for Debris and Contamination.
   
Debris or Contamination    
Result: The Y-sediment strainer has debris or contamination.

Repair: Repair or replace the Y-sediment strainer as needed.
Verify that the repair eliminates the problem.

Result: The Y-sediment strainer does not have any debris or contamination.

Proceed to Test Step 7.
   

7. Check the DEF Dosing Pump for Normal Operation
   
Normal pump operation    
Result: The dosing pump is operating correctly.

STOP

Result: The dosing pump is not operating correctly.

Repair: Repair or replace the DEF dosing pump as needed. Refer to dealerconnect.cat.com for more information on the GRUNDFOS ALLDOS DATA BOOKLET.
Note: Check calibration prior to repairing the pump.
Verify that the repair eliminates the problem.
   

Solenoids Are Not Functioning

Probable Causes

  • Crystallized DEF

  • Electrical fault

Recommended Actions

Sometimes DEF can back flush into a dosing cabinets plumbing and crystallize inside different components.

Without the air solenoid being open does two things:

1. DEF will crystallize in the delivery system

2. DEF will not atomize

While the engine is not generating power, the dosing cabinet should be in "Standby" mode. If the air or purge gauge is showing air pressure or the sound of air is leaking through the system, most likely a solenoid is not all the way closed. One sure way to verify that the solenoid is not all the way closed is to remove the delivery lines going to the injector assembly.

Note: The procedures have been listed in order of probability. Complete the procedures in the order of the listed test steps.

Table 7
Troubleshooting Test Steps     Values     Results    

1. Verify that Power is on in the Dosing Cabinet .

A. Verify that power is on in the cabinet .
   

Power
   

Result: The power is on in the dosing cabinet.

Proceed to Test Step 2.

Result: The power is not on in the dosing cabinet.

Repair: Repair or replace fuses or breakers.
Verify that the repair eliminated the problem.
   

2. Inspect the Electrical Connectors and the Wiring


A. Remove electrical power from the dosing cabinet.
   

Damage to wiring and/or connectors
   

Result: The connectors and wiring appear to be OK.

Proceed to Test Step 3.

Result: There is a problem in the connectors and/or wiring.

Repair:The connectors or wiring and/or replace the connectors or wiring. Ensure that all of the seals are properly in place and ensure that the connectors are coupled.
Verify that the repair eliminated the problem.
   

3. Check for a Fault or Status Code

A. Connect computer to the dosing cabinet.

B. Check the "SYSTEM STATUS " window on the operations page for faults.
   

Check for a Fault or Status Code
   

Result No fault or status code is present.


Proceed to Test Step 4.

Result A fault or status code is present.

Repair: Repair or replace the necessary components.
Verify that the repair eliminated the problem.
   

4. Verify that the Dosing Cabinet Controller is in Setup Mode.
   
Setup Mode    
Result: The dosing cabinet controller is in setup mode.

Proceed to Test Step 5.

Result: The dosing cabinet controller is not in setup mode.

Repair: Put the dosing cabinet controller into setup mode and cycle the solenoids.
Verify that the repair eliminated the problem.
   

5. Check the Voltage to the Air and Purge Solenoids

A. Disconnect the electrical connector from the solenoid.

B. Connect a multimeter to the electrical connector going to the solenoid.

C. Click the radio button corresponding to the solenoid.
   

12V
   

Result: 12V is present.

Proceed to Test Step 6.

Result: 12V is not present.

Repair: Replace the dosing cabinet controller.
Verify that the repair eliminated the problem.
   

6. Inspect the Air Solenoid for Crystallized DEF

A. Turn off the power to the dosing cabinet.

B. Turn off the air supply ball valve.

C. Unplug the solenoid coil from the power supply.

D. Remove the coil retainer nut and washer.

E. Remove the solenoid coil.

F. Use a pair of channel locks to remove the valve stem from the top of the solenoid body. Turn the valve stem in a counter clock wise direction until loose.

G. Inspect valve stem for crystallized DEF.

H. Inspect the inside of the valve stem for crystallized DEF.

I. Inspect the housing and plunger seat of the solenoid for deformities. If damage is present replace solenoid.

J. Reassemble solenoid in reverse procedure.

K. Turn the air and power back to the on positions. Test the solenoids through the webpage.
Refer to Systems Operation / Testing and Adjusting, UENR4332, "Air and Purge Solenoid" for more information.
   

Crystallized DEF
   

Result: The valve stem is crystallized with DEF.

Repair: Clean with warm water removing all contaminants and DEF deposits. Or, replace the solenoid.
Verify that the repair eliminated the problem.

Result: The valve stem is not crystallized with DEF.

Result: The inside of the valve stem is crystallized with DEF.

Repair: Clean with warm water removing all contaminants and DEF deposits. Or, replace the solenoid.
Verify that the repair eliminated the problem.

Result: The inside of the valve stem is not crystallized with DEF.
   

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