04 WRX Fuel Pump Fuse: Location, Diagnosis, and Replacement Guide

If your 2004 Subaru WRX won't start or stalls while driving, the fuel pump fuse is one of the first things you should check. The fuel pump fuse for a 2004 Subaru Impreza WRX is located in the fuse and relay box behind the left side of the dashboard, on the driver's side. It is typically a 15A or 20A blade-type fuse, and it may be labeled as "FUEL PUMP" or "FP" in the fuse box diagram . The fuel pump relay is also located in this same fuse box . A blown fuse will cut power to the fuel pump, causing the engine to crank but not start, or to stall unexpectedly .

1. Where is the 2004 WRX Fuel Pump Fuse?

The main fuse box for the 2004 Subaru Impreza WRX is located behind the coin tray on the driver's side of the dashboard . To access it:

  1. Open the driver's side door.
  2. Locate the small coin tray on the dashboard, near the door opening.
  3. Open the cover and pull the coin tray straight out to expose the fuse panel .

What you need to know about the fuel pump fuse:

  • Location: Inside the interior fuse box (cabin fuse box), behind the left side of the dash .
  • Fuse Rating: 15A or 20A, depending on the specific model year and trim .
  • Labeling: Look for "FUEL PUMP," "FP," or "F-PUMP" on the fuse box diagram sticker .
  • Diagram Reference: In the 2004 power distribution diagrams, the fuel pump fuse is listed as part of the fuse and relay box (F/B) behind the left side of the dash .

Important Note: Some 2004 WRX models may also have a secondary fuse or relay for the fuel pump in the engine bay fuse box, located near the battery on the driver's side . Check your owner's manual for the exact layout of your specific vehicle.

2. How to Identify a Blown Fuel Pump Fuse

The symptoms of a blown fuel pump fuse are very similar to a failing fuel pump itself. Here are the most common signs:

1. No Start Condition: The engine cranks over normally (the starter motor works), but the engine will not fire up. You won't hear the fuel pump prime when you turn the key to the "ON" position .
2. Engine Stalling: If the fuse blows while driving, the engine will suddenly lose power and stall. You will lose all engine power, but the electrical systems (lights, radio) will usually still work .
3. Fuel Pump Relay Issues: The fuse and relay work together. If the fuse is good but the fuel pump still doesn't run, the relay itself may be faulty. The fuel pump relay is also located in the same fuse box behind the dashboard .

3. How to Check and Replace the Fuel Pump Fuse

Replacing a fuse is a simple, zero-cost diagnostic step that every WRX owner should know.

Step 1: Pull the fuse. Use a fuse puller tool (usually found inside the fuse box cover or in the engine bay fuse box) or a pair of needle-nose pliers. Gently pull the fuse straight out .

Step 2: Inspect the fuse. Hold the fuse up to a light. Look through the transparent plastic body. If the metal strip inside is broken or melted, the fuse is blown .

Step 3: Replace the fuse. Always replace a blown fuse with one of the exact same amperage rating. Never use a higher-rated fuse (e.g., don't replace a 15A fuse with a 20A one), as this can cause wiring damage or a fire .

Step 4: Test the system. After replacing the fuse, try to start the car. If the new fuse blows immediately, you have a short circuit in the fuel pump wiring or the fuel pump itself, and you will need professional diagnosis .

4. What Causes the Fuel Pump Fuse to Blow?

A blown fuse is a symptom of a deeper problem. Common causes include:

  • A failing fuel pump: As the fuel pump motor wears out, it can draw too much current, causing the fuse to blow .
  • Short circuits: Damaged or chafed wiring to the fuel pump (usually in the fuel tank or under the car) can cause a short to ground .
  • Corroded connectors: Moisture and corrosion in the fuel pump electrical connector at the top of the fuel tank can create resistance, leading to overheating and fuse failure.
  • A clogged fuel filter: A severely restricted fuel filter can cause the pump to work harder and draw more current, potentially blowing the fuse.

5. Where is the Fuel Pump Located?

If the fuse keeps blowing, the problem is likely the fuel pump itself. On a 2004 Subaru WRX, the fuel pump is located inside the fuel tank .

To access the fuel pump assembly:

  1. Remove the rear seat bottom cushion (two 12mm bolts) and the rear seat back cushion (four 12mm bolts) .
  2. Remove the plastic/rubber cover on the passenger side of the floor behind the rear seat.
  3. You will see a metal access plate held in place by four Philips screws. Remove the screws .
  4. Underneath is the fuel pump assembly. You will need to disconnect the electrical connector, fuel lines, and then unbolt the locking ring to remove the entire pump assembly .

6. OEM Fuel Pump Specifications for the 2004 WRX

Knowing your stock specs can help you choose the right replacement part.

  • Flow Rate: The stock 2004 WRX fuel pump flows approximately 130 liters per hour (LPH) .
  • Fuel Pressure: The factory fuel pressure regulator keeps the pressure at the stock 43 psi plus manifold pressure .
  • Injector Size: The stock 2004 WRX uses 420 cc injectors .

Important: Do not replace the fuel pump fuse with a higher amperage fuse if you upgrade to a high-flow fuel pump. An upgraded pump (like a Walbro 255 LPH) will draw more current. In that case, you should install a fuel pump hardwire kit, which includes a properly rated fuse and relay, to safely provide the necessary power .

7. Upgrade Your Fuel System with KEMSO

If you've determined that the fuel pump itself is the root cause of your blown fuse, or if you're simply looking to upgrade for better performance and reliability, it's time to replace the unit. The stock pump on a 2004 WRX is a 130 LPH unit, which is adequate for stock power levels, but it can become a weak point as the car ages.

Why choose KEMSO for your 2004 WRX fuel pump?

KEMSO offers a high-performance, direct OEM replacement fuel pump designed specifically for the Subaru Impreza (1998-2023). Unlike cheap, generic pumps that may not fit correctly or deliver consistent flow, KEMSO fuel pumps are engineered to meet or exceed original equipment specifications. When you are dealing with a faulty fuel pump causing a blown fuse, you need a reliable replacement that will last. KEMSO's fuel pumps are high-performance components that provide a perfect, bolt-in fit. They are designed to handle the demands of both daily driving and spirited performance.

Best of all, every KEMSO fuel pump comes with a lifetime warranty. This means you can install it with complete confidence, knowing that your investment is protected for as long as you own the vehicle. Stop wasting time on unreliable parts and buy a pump that is built to last.

Visit KEMSO today to find the perfect fuel pump for your 2004 Subaru WRX: https://www.kemsoracing.com/

8. Final Checklist

If you are dealing with a no-start or stalling issue on your 2004 WRX, follow this checklist:

  1. Check the fuel pump fuse (15A or 20A) in the interior fuse box behind the driver's side coin tray .
  2. Check the fuel pump relay in the same fuse box .
  3. Listen for the fuel pump prime when you turn the key to "ON."
  4. If the fuse blows again, inspect the wiring and connectors at the fuel pump assembly for damage or corrosion.
  5. Replace the fuel pump if it is the source of the electrical draw. A high-quality replacement like a KEMSO fuel pump is a smart, long-term solution.

For the best replacement fuel pump for your 2004 Subaru WRX, backed by a lifetime warranty, visit KEMSO Racing at https://www.kemsoracing.com/.


Back to blog