GUARD AS 2532987 - Caterpillar

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.
Start the engine. Activate the "ARD Nozzle Heater Test".
Record the current reading on the ammeter.
Disable the "ARD Nozzle Heater Test". Stop the engine. Remove the clamp-ammeter.
Disconnect the electronic service tool.Expected Result:The current flow is above 3.5 Amps.Results:
The current flow is above the minimum amount for the appropriate system voltage. - The current flow is OK. Proceed to Test Step 5.
The current flow is below the expected amount for the appropriate system voltage. - The current flow is low.Repair: Determine the cause of the low current flow. Refer to Troubleshooting, "ARD Nozzle Heater - Test".STOPTest Step 5. Inspect the ARD Combustion Head
Remove the ARD combustion head. Refer to Disassembly and Assembly, "Combustion Head Group (ARD) - Remove and Install".
Inspect the fuel nozzle for excessive carbon deposits.Note: Do not attempt to clean the fuel nozzle.Results:
The fuel nozzle is not blocked with excessive carbon deposits. - Install the ARD combustion head. proceed to Test Step 6.
The fuel nozzle is blocked with excessive carbon deposits. - Repair: Perform the following procedure:
Install the ARD combustion head. Refer to Disassembly and Assembly, "Combustion Head Group (ARD) - Remove and Install".
Run the engine. Use the electronic service tool to perform the "Aftertreatment #1 Fuel Injector #1 Heater Override" to clean the fuel nozzle.Note: The "Aftertreatment #1 Fuel Injector #1 Heater Override" will take 1 hour to complete.
Perform an "ARD Ignition Test" and confirm the fault has been eliminated.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.
If the fault is still present, install a replacement ARD combustion head. Refer to Disassembly and Assembly, "Combustion Head Group (ARD) - Remove and Install".
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.
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.
Confirm that the fault has been eliminated.STOPTest Step 6. Replace the ARD Combustion Head Filter Connector
Replace pilot filter connector (7) in the ARD combustion head. Refer to Illustration 2.
Clear all diagnostic codes.
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.
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