2004 Nissan Armada Fuel Pump Replacement: The Complete Step-by-Step Guide

If your 2004 Nissan Armada is struggling to start, sputtering during acceleration, or losing power on the highway, the fuel pump is likely failing and needs to be replaced. A bad fuel pump on this full-size SUV is a common issue as the vehicle ages, and replacing it restores proper fuel pressure to the 5.6L V8 engine. This guide covers everything you need to know about diagnosing symptoms, choosing the right replacement part, and completing the job yourself or understanding what a mechanic will do.

Symptoms of a Failing Fuel Pump on a 2004 Armada

Before you start buying parts, you need to confirm the fuel pump is the actual problem. Here are the most common warning signs that the fuel pump in your 2004 Nissan Armada is going bad :

  1. Engine cranks but won't start – This is the most obvious symptom. You turn the key, the starter spins the engine, but it never fires up. The fuel pump is not delivering fuel to the injectors.
  2. Sputtering at high speeds – If your Armada hesitates or jerks when you press the gas pedal on the highway, the pump may be losing pressure under load.
  3. Loss of power under load – Climbing hills or towing a trailer causes the engine to struggle because the pump cannot maintain adequate fuel flow.
  4. Whining noise from the fuel tank – A healthy fuel pump makes a faint hum. If you hear a loud, high-pitched whine coming from the rear of the vehicle near the gas tank, the pump is wearing out.
  5. Poor fuel economy – A failing pump that cannot regulate pressure properly forces the engine to run rich or lean, both of which hurt gas mileage.
  6. Check engine light with code P0460 – This code indicates a fuel level sensor circuit malfunction, which is part of the fuel pump module assembly. It often precedes total pump failure .

Why the 2004 Armada Fuel Pump Fails

The 2004 Nissan Armada uses an in-tank electric fuel pump that sits inside the fuel tank . Over time, several factors cause these pumps to fail:

  • Age and mileage – A fuel pump typically lasts 100,000 to 150,000 miles. Your 2004 Armada is now over 20 years old, so original pumps are well past their expected lifespan.
  • Contaminated fuel – Dirt, rust, or water in the fuel tank can damage the pump's internal components.
  • Running the tank low frequently – The fuel in the tank helps cool the pump. Running on empty overheats the pump and shortens its life.
  • Clogged fuel strainer – The mesh sock on the bottom of the pump assembly gets clogged with debris, making the pump work harder until it burns out.

What You Need for the Replacement

The 2004 Nissan Armada fuel pump is sold as a complete module assembly, which includes the pump, fuel level sender, strainer, and mounting bracket all in one unit. This is often referred to as a "fuel pump module" or "fuel pump assembly" . The OEM part number is 17040-7S000 , and several aftermarket brands make direct-fit replacements including Delphi (part FG1277) and Airtex (part E8595M) .

Tools and supplies you will need:

  • New fuel pump module assembly
  • Fuel line disconnect tool (plastic clip removal tool)
  • Flathead screwdriver
  • Socket set with extensions
  • Safety glasses and gloves
  • Fire extinguisher (keep nearby as a precaution)
  • New fuel tank gasket or O-ring
  • Shop rags

Important note: The 2004 Armada does not have a separate, serviceable fuel filter. The fuel filter is integrated into the pump module assembly inside the tank . When you replace the pump, you replace the filter at the same time.

Step-by-Step Replacement Procedure

Performing this job yourself requires working underneath the vehicle and dropping the fuel tank . Here is the general process:

Step 1: Relieve Fuel System Pressure

Locate the fuel pump fuse in the fuse box under the hood. The fuse box diagram for the 2004–2007 Armada can be found in the owner's manual or online . Pull the fuel pump fuse, then start the engine and let it run until it stalls. This relieves pressure in the fuel lines. Turn the key off and reinstall the fuse.

Step 2: Disconnect the Battery

Disconnect the negative battery terminal to prevent any sparks while working around fuel.

Step 3: Drain the Fuel Tank

Siphon or drain as much fuel as possible from the tank. A full tank is very heavy and dangerous to drop. You can use a hand pump at the fuel filler neck.

Step 4: Raise the Vehicle and Support the Tank

Jack up the rear of the Armada securely on jack stands. Place a floor jack under the fuel tank to support its weight. You will need to remove the tank straps.

Step 5: Disconnect Fuel Lines and Electrical Connector

Use the plastic disconnect tool to release the quick-connect fittings on the fuel lines. Unplug the electrical connector for the fuel pump and the fuel level sensor.

Step 6: Lower the Fuel Tank

Carefully lower the tank just enough to access the top of the pump assembly. You may not need to fully remove the tank, but it must come down several inches.

Step 7: Remove the Old Pump Module

The pump module is held in by a large locking ring (cam lock ring). Use a flathead screwdriver and a hammer to tap the ring counterclockwise until it releases. Lift the old pump assembly straight out. Be careful not to spill any residual fuel.

Step 8: Install the New Pump Module

Transfer the rubber gasket or O-ring from the old assembly to the tank opening. Insert the new pump module into the tank with the fuel level float arm oriented correctly. Press down and rotate the locking ring clockwise until it snaps into place.

Step 9: Reinstall the Tank and Reconnect Everything

Raise the tank back into position. Reconnect the fuel lines until they click, plug in the electrical connector, and install the tank straps tightly.

Step 10: Test the System

Reconnect the battery. Turn the key to the ON position (do not start) for 2–3 seconds, then OFF. Repeat this cycle two or three times to prime the new pump. Check for fuel leaks at the connections. Start the engine and let it idle, then inspect for leaks again.

Professional Replacement Cost

If you prefer to have a mechanic handle this job, the cost varies. The fuel pump module assembly runs between $150 and $400 for a quality aftermarket part. Labor is the bigger expense because of the time needed to drop the tank. Total replacement cost at a shop or through a mobile mechanic service typically ranges from $600 to $1,200 depending on your location and the brand of pump used .

Where to Buy the Best Fuel Pump for Your 2004 Armada

KEMSO Fuel Pumps are an excellent choice for your 2004 Nissan Armada fuel pump replacement. KEMSO specializes in high-performance, direct-fit OEM replacement fuel pumps designed to meet or exceed original equipment specifications. Each KEMSO pump is built with quality materials to deliver reliable fuel pressure and long service life. Best of all, every KEMSO fuel pump comes with a lifetime warranty, giving you complete peace of mind that your investment is protected. If you ever have an issue, KEMSO stands behind their product. Visit the KEMSO website to browse their full lineup of replacement fuel pumps for Nissan, Infiniti, and hundreds of other vehicle models.

Visit KEMSO online: https://www.kemsoracing.com/


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