C7.1 Industrial Engine and Generator Set Caterpillar

This procedure covers the following diagnostic code:

The ARD nozzle can become plugged with carbon or with debris. The Electronic Control Module (ECM) periodically tests the condition of the nozzle. The engine is equipped with a system that cleans the nozzle. A restriction in a filter connector for the ARD combustion head can also set this code.

Electric Heating Element - The ARD combustion head contains an electric heating element. The heating element operates periodically in order to clean the nozzle.

Features on the Electronic Service Tool

ARD Nozzle Heater Test - This process activates the output for the heated nozzle in order to test the nozzle heater circuit. The output only remains activated when selected on the electronic service tool. The heat cycle stops if the engine is stopped.

ARD Fuel Nozzle Heater Override - This process activates the output for the heated nozzle in order to clean the nozzle. The output remains activated for approximately 1 hour. The heat cycle stops if the engine is stopped. The heat cycle continues when the engine is started. Active regenerations will not occur until the heat cycle is complete.

ARD Ignition Test - The test operates the ARD for approximately 5 minutes while the engine is running. The test determines if the ARD can generate heat. If the ARD cannot generate heat, a diagnostic code is activated. The code indicates the specific problem with the ARD.

Test Step 1. Check for Active or Recently Logged Diagnostic Codes

1. Turn the keyswitch to the ON position.

2. Establish communication between the electronic service tool and the ECM . Refer to Troubleshooting, "Electronic Service Tools", if necessary.

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

   • Aftertreatment Regeneration Trigger History

   • Product Status Report with Histograms

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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. 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 a 3556-7 diagnostic code was logged. - Proceed to Test Step 2.

• The "ARD Ignition Test" was not successful and another diagnostic code was logged. -

  Repair: Troubleshoot the other diagnostic codes. Refer to Troubleshooting, "Diagnostic Trouble Codes".

  STOP

Test Step 2. Check the Current Flow Through the ARD Nozzle Heater

1. Turn the keyswitch to the OFF position.

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Illustration 1	g02231813
Typical view of the ARD combustion head (1) Insulated part of the heater wire

2. Connect a suitable clamp-ammeter around the insulated part of the heater wire (1) .

3. Turn the keyswitch to the ON position.

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NOTICE
Do not energize the heater for more than 30 seconds. If the heater is energized more than 30 seconds, damage to the heater can occur. Allow the heating element to cool for 2 minutes between power cycles.

4. Use the "ARD Nozzle Heater Test" in the electronic service tool to switch on the ARD nozzle heater.

5. Record the current reading on the ammeter.

6. Use the "Aftertreatment #1 Fuel Injector #1 Heater Override" in the electronic service tool to switch off the ARD nozzle heater.

Expected Result:

The ammeter should read at least 7 amps for a 12 V system or 3.5 Amps for a 24 V system.

Results:

• OK - The current is correct for the system. The ARD nozzle heater is operating correctly. Proceed to Test Step 3.

• Not OK - The current is below the expected level for the system.

  Repair: Diagnose and repair the fault with the ARD nozzle heater circuit. Refer to Troubleshooting, "ARD Nozzle Heater - Test".

  When the nozzle heater circuit has been repaired, proceed to Test Step 4.

Test Step 3. Replace the ARD Filter Connector in the ARD Combustion Head

Illustration 2	g02231814
Typical view of the ARD combustion head (2) Pilot filter connector

1. Replace pilot filter connector (2) in the ARD combustion head

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 a 3556-7 diagnostic code was logged. - Proceed to Test Step 5.

• The "ARD Ignition Test" was not successful and another diagnostic code was logged. -

  Repair: Troubleshoot the other diagnostic codes. Refer to Troubleshooting, "Diagnostic Trouble Codes".

  STOP

Test Step 4. Perform an ARD Nozzle Heat Cycle

1. Start the engine.

Note: The ECM must have an engine speed signal to initiate the ARD nozzle heater cycle.

2. Initiate the cycle for the ARD nozzle heater. The cycle for the ARD nozzle heater will cycle the nozzle ON and OFF for an hour in order to clean the nozzle.

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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. When the "ARD Nozzle Heat Cycle" is complete, use the electronic service tool to perform an "ARD Ignition Test".

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 a 3556-7 diagnostic code was logged. - Proceed to Test Step 5.

• The "ARD Ignition Test" was not successful and another diagnostic code was logged. -

  Repair: Troubleshoot the other diagnostic codes. Refer to Troubleshooting, "Diagnostic Trouble Codes".

  STOP

Test Step 5. Replace the ARD Combustion Head

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

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 fault is still present -

  Repair: Contact the technical communicator at a Caterpillar dealer.

  STOP