What is 4576-3(1) CAT Code & How to Solve It?

What is 4576-3(1) CAT Code:

CAT Code 4576-3 indicates a fault with the Aftertreatment Fuel Injector — specifically, a voltage above normal condition in circuit number 1.

This code means the fuel injector used during active regeneration is receiving more voltage than it should, which could lead to overheating or injector malfunction, resulting in failed regens and increased soot load.

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Why This Happens

• Electrical short in the injector power circuit.
• Voltage spikes due to faulty alternator or ECM.
• Failing aftertreatment injector driver.
• Loose or corroded connector causing resistance.
• Faulty injector with internal electrical fault.

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How to Fix It

1. Inspect wiring and connectors for visible damage or burn marks.
2. Test voltage at the injector connector during regen.
3. Replace injector if voltage remains too high.
4. Test alternator output for overvoltage spikes.
5. Clear the code and test regeneration function after repairs.

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How to Avoid It Before It Happens

1. Regularly inspect aftertreatment wiring for signs of damage.
2. Protect electrical connectors from corrosion and vibration.
3. Replace injectors showing early signs of electrical failure.
4. Check voltage stability across the system during routine diagnostics.