C7.1 Industrial Engine and Generator Set Caterpillar

Use this procedure to troubleshoot the following code:

System Operation

The combustion air system routes pressurized air from the outlet of the high-pressure turbocharger to the ARD. The combustion air is mixed with fuel inside the ARD combustion head. The air/fuel mixture is ignited and the air/fuel mixture is burned in order to increase the temperature of the exhaust gas. The high temperature exhaust gas burns off the soot in the Diesel Particulate Filter (DPF). This process is known as DPF regeneration.

The ECM sends a pulse width modulated signal to the combustion air valve. The actuator in the combustion air valve regulates the combustion air to the ARD combustion head.

The ECM also sends pulse width modulated signals to the pilot fuel control valve. The pilot fuel control valve regulates the amount of fuel that is injected into the ARD combustion head.

The ECM controls the ARD ignition system. Whenever the ARD is required to operate, the ECM operates the ARD ignition coil which then generates high voltage pulses in the ignition cable. The high voltage pulses create sparks at the spark plug in the ARD head. The spark ignites the fuel/air mixture in the ARD.

If the amount of fuel or air that enters the ARD combustion head is incorrect or there are no ignition sparks, combustion may not occur.

Test Step 1. Check for Associated Diagnostic Trouble Codes

1. Establish communication between the electronic service tool and the engine ECM.

2. Download the following items before performing any troubleshooting or clearing any diagnostic codes:
   • Warranty Report

   • Aftertreatment Regeneration Trigger History

   • Product Status Report with Histograms

3. Use the electronic service tool to check for active diagnostic codes.

4. Table 2 lists the diagnostic trouble codes that are associated with the "3473-31 Aftertreatment #1 Failed to Ignite" code. Determine if any of the codes in Table 2 are present.

Results:

• An associated diagnostic trouble code is not present. - Proceed to Test Step 2.

• An associated diagnostic trouble code is present. -

  Repair: Refer to Troubleshooting, "Diagnostic Trouble Codes" in order to troubleshoot the associated diagnostic code.

  STOP

Test Step 2. Inspect the ARD Ignition System

1. Visually inspect the components for the ARD ignition system. Check for the following faults:
   • Loose connections or damaged connectors

   • Moisture on the connectors or the wiring

   • Damage caused by excessive heat

   • Damage caused by chafing

   • Incorrect routing of wiring

   • Damaged insulation

2. Verify that each end of the ground wire is securely connected to both ground points.

3. Push the boot on each end of the ignition wire. There should not be a "click" when you push the boot onto either part. If a "click" is felt, the clip inside the boot was not connected.

4. Perform a 45 N (10 lb) pull test on each harness wire at the 3-pin connector for the ignition coil.

Results:

• The wiring is not OK. - There is a fault in the wiring. A wire end is not connected or a wire is damaged. Repair the wiring. If necessary, replace any damaged parts. Proceed to Test Step 9.

• The wiring is OK. - Proceed to Test Step 3.

Test Step 3. Check the Current Flow to the ARD Nozzle Heater

1. Verify that the engine is off.

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Illustration 1	g02856716
Measuring the current flow (1) ARD combustion head (2) Metal part of heater wire (3) Insulated part of heater wire

2. Connect a suitable clamp-ammeter around the insulated part of the heater wire (3) . Make sure that the jaws of the ammeter are away from the metal part of the heater wire (2) .

3. Establish communication between the electronic service tool and the ECM. Refer to Troubleshooting, "Electronic Service Tools" for the proper procedure.

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The ignition system may cause an electrical shock hazard, which may cause personal injury or death. Avoid contacting the ignition system components and the ignition system wiring during operation.

4. Start the engine. Activate the "ARD Nozzle Heater Test".

5. Record the current reading on the ammeter.

6. Disable the "ARD Nozzle Heater Test". Stop the engine. Remove the clamp-ammeter.

7. Disconnect the electronic service tool.

Results:

• The ammeter reads at least 7 Amps for a 12 VDC system or 3.5 Amps for a 24 VDC system. - The current consumption is normal. Proceed to Test Step 4.

• The ammeter reads less than 7 Amps for a 12 VDC system or 3.5 Amps for a 24 VDC system. -

  Repair: Investigate the cause of the low current consumption. Refer to Troubleshooting, "ARD Nozzle Heater - Test".

  STOP

Test Step 4. Check for Voltage at the Spark Plug

Illustration 2	g02856717
368-6232 Spark Indicator (4) Connector for spark plug (5) Spark window (6) Connector for ignition wire

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NOTICE
If the engine is running, the ARD spark plug will continue to fire. Turn the key to the OFF position before servicing the ARD spark plug.

1. Disconnect the ignition wire from the ARD spark plug.

2. Connect the spark indicator between the ignition wire and the ARD spark plug.

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The ignition system may cause an electrical shock hazard, which may cause personal injury or death. Avoid contacting the ignition system components and the ignition system wiring during operation.

3. Use the "ARD Ignition Transformer Primary Status" override on the electronic service tool to turn on the ARD ignition system.

Expected Result:

The spark indicator flashes.

Results:

• The spark indicator flashes. - Turn off the ARD ignition system by disabling the override. Proceed to Test Step 5.

• The spark indicator does not flash. -

  Repair: Proceed to Troubleshooting, "ARD Ignition - Test".

  STOP

Test Step 5. Clean the Components in the ARD Combustion Head

Illustration 3	g02856718
Use of the plug bore brush (7) ARD combustion head (8) Ground probe (9) 305-2389 Plug Bore Brush

Illustration 4	g02856719
(10) Flame detection temperature sensor

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NOTICE
If the engine is running, the ARD spark plug will continue to fire. Turn the key to the OFF position before servicing the ARD spark plug.

1. Remove the spark plug from the ARD combustion head.

2. Clean ground probe (2) inside ARD combustion head (1) by running 305-2389 Plug Bore Brush (3) through the hole in the ARD combustion head. Run the brush through the hole several times. Refer to Illustration 3.

3. Inspect the spark plug. Look for the following defects:

   Carbon Deposits - Use a nonmetallic cleaning pad to clean the spark plug.

   Bent Probe - Check the probe for damage.

   Damaged Insulator - Check the insulator for damage.

   Note: The spark plug may be damaged if the spark plug is dropped. Do not install a spark plug that has been dropped.

4. Remove flame detection temperature sensor (10) .

5. Clean the flame detection temperature sensor. Use a nonmetallic cleaning pad to clean the sensor.

6. Install the flame detection temperature sensor.

Expected Result:

The components are clean and the spark plug is not visibly damaged.

Results:

• Result 1: The components are clean and the spark plug is not visibly damaged. -

  Repair: Perform the following procedure:

  1. Install the original spark plug.

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  The ignition system may cause an electrical shock hazard, which may cause personal injury or death. Avoid contacting the ignition system components and the ignition system wiring during operation.

  2. Use the electronic service tool to perform an ARD ignition test.

     Note: The ARD Ignition Test cannot be performed if the DPF soot loading is above 80%. When the DPF soot loading is above 80%, use the electronic service tool to perform a Manual DPF Regeneration.

  3. Confirm that the fault has been eliminated.

  4. If the fault is still present, install a replacement spark plug. Refer to Specifications, "Electronic Control Wiring Group (ARD)" for the correct torque value.

  5. Use the electronic service tool to perform an ARD ignition test.

     Note: The ARD Ignition Test cannot be performed if the DPF soot loading is above 80%. When the DPF soot loading is above 80%, use the electronic service tool to perform a Manual DPF Regeneration.

  6. Confirm that the fault has been eliminated.

  If the fault is still present, install the original spark plug. Proceed to Test Step 6.

• Result 2: The spark plug is damaged. -

  Repair: Perform the following procedure:

  1. Install a replacement spark plug. Refer to Specifications, "Electronic Control Wiring Group (ARD)" for the correct torque value.

  2. Use the electronic service tool to perform an ARD ignition test.

     Note: The ARD Ignition Test cannot be performed if the DPF soot loading is above 80%. When the DPF soot loading is above 80%, use the electronic service tool to perform a Manual DPF Regeneration.

  3. Confirm that the fault has been eliminated.

  If the fault is still present, proceed to Test Step 6.

Test Step 6. Check the ARD Air System

Use the electronic service tool to perform the ARD Air System Service Test.

Results:

• The ARD Air System Service Test is successful. - Proceed to Test Step 7

• The ARD Air System Service Test is failed. -

  Repair: Investigate the cause of the test failure. Refer to Troubleshooting, "ARD Combustion Supply Air Pressure Is Low".

  STOP

Test Step 7. Replace the ARD Filter Connector in the ARD Combustion Head

Illustration 5	g02931757
ARD Combustion Head (11) ARD pilot filter connector

1. Replace pilot filter connector (11) in the ARD combustion head. Refer to Illustration 5.

2. Clear all diagnostic codes.

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The ignition system may cause an electrical shock hazard, which may cause personal injury or death. Avoid contacting the ignition system components and the ignition system wiring during operation.

3. Use the electronic service tool in order to perform the "ARD Ignition Test".

   Note: The ARD Ignition Test cannot be performed if the DPF soot loading is above 80%. When the DPF soot loading is above 80%, use the electronic service tool to perform a Manual DPF Regeneration.

Results:

• The ARD ignition test was successful and no codes were logged. - Return the unit to service.STOP

• The ARD ignition test was not successful and codes were logged. - Proceed to Test Step 8.

Test Step 8. Inspect ARD Swirl Plate

Illustration 6	g02865416
(12) Swirl plate slots

1. Remove the ARD head. Refer to Disassembly and Assembly, "Combustion Head Group (ARD) - Remove and Install - Clean Emissions Module" for the proper procedure to remove the ARD combustion head.

Note: Soot accumulation is normal. Slot fouling is defined as more than 1/2 the inner row slots being 100 percent blocked. Partially blocked inner row slots are normal and do not affect regeneration performance. Refer to Illustration 6.

2. Inspect the swirl plate for fouled slots (12) .

Results:

• The swirl plate is fouled. -

  Repair: Perform the following procedure:

  1. Clean the swirl plate. Refer to Testing and Adjusting, "Swirl Plate (ARD Combustion) - Inspect/Clean ".

  2. Install the ARD head. Refer to Disassembly and Assembly, "Combustion Head Group (ARD) - Remove and Install - Clean Emissions Module".

  3. Reset all active codes and clear all logged codes. Use the electronic service tool to perform the "ARD Ignition Test" and verify that there are no fuel leaks.

     Note: The ARD Ignition Test cannot be performed if the DPF soot loading is above 80%. When the DPF soot loading is above 80%, use the electronic service tool to perform a Manual DPF Regeneration.

  Proceed to Test Step 9.

• The swirl plate is not fouled. -

  Repair: Perform the following procedure:

  1. Replace the ARD combustion head. Refer to Disassembly and Assembly, "Combustion Head Group (ARD) - Remove and Install".

  2. Reset all active codes and clear all logged codes. Use the electronic service tool to perform the "ARD Ignition Test" and verify that there are no fuel leaks.

     Note: The ARD Ignition Test cannot be performed if the DPF soot loading is above 80%. When the DPF soot loading is above 80%, use the electronic service tool to perform a Manual DPF Regeneration.

  Proceed to Test Step 9.

Test Step 9. Perform a Manual DPF Regeneration

Note: This test must be performed through the electronic service tool. The electronic service tool enhances the diagnostics during the service test.

1. Clear all diagnostic codes.

2. Click the "Disconnect" icon on the electronic service tool in order to disconnect the electronic service tool from the engine.

3. Turn the keyswitch to the OFF position. Wait for 5 seconds.

4. Turn the keyswitch to the ON position.

5. Click the "Connect" icon on the electronic service tool.

6. Start the engine. Allow the engine to idle for 3 minutes.

Note: Do not use the operators switch for a stationary regeneration. The service tests provide enhanced diagnostics that are necessary for proper troubleshooting and repair.

7. Start a "Manual DPF Regeneration" in the electronic service tool.

   Note: The ECM tests the nozzles for plugging after the "Manual DPF Regeneration" is complete. Approximately 10 minutes are required in order for the test to provide a result. A code will become active if the nozzles are plugged.

Results:

• The "Manual DPF Regeneration" completed successfully. There are no additional codes. - The system is operating correctly.STOP

• The "Manual DPF Regeneration" did not complete successfully. There are additional diagnostic codes. -

  Repair: Troubleshoot the additional diagnostic codes before returning the unit to service. Refer to Troubleshooting for the correct procedure.Verify that the fault has been eliminated.

  STOP