2004 Honda Accord Fuel Pump Relay Location: Where to Find It and How to Fix It Fast

If your 2004 Honda Accord cranks but won't start, the most likely culprit is the fuel pump relay, not the fuel pump itself. On the 2004 Honda Accord, the fuel pump relay is located inside the under-dash fuse/relay box on the driver's side, behind the kick panel below the steering column. For the 2003-2007 2.4L models, this relay is actually part of a larger component called the PGM-FI Main Relay, which controls both the engine computer and the fuel pump . Before you spend hundreds of dollars on a fuel pump replacement, checking and swapping this relay should be your very first step.

Why the Fuel Pump Relay Matters

The fuel pump relay acts as a remote-controlled switch. When you turn the key to the ON position, your car's Engine Control Unit (ECU) sends a small electrical signal to the relay. The relay then closes a circuit, allowing full battery power to flow directly to the fuel pump in the gas tank . Without a working relay, the fuel pump never gets power, no fuel reaches the engine, and your car simply won't start.

Here is the bottom line: relay failure is far more common than fuel pump failure on these Honda Accords . The contacts inside the relay can corrode or weld together over time, especially in older vehicles like a 2004 model. When that happens, the relay stops doing its job. The good news is that a replacement relay costs around $20 to $40 rather than the $300 to $600 you might spend on a fuel pump you do not actually need .

Symptoms of a Bad Fuel Pump Relay

Knowing the symptoms helps you avoid guessing and throwing money at the wrong part. If your 2004 Accord has any of these issues, the fuel pump relay should be your first suspect:

1. Engine Cranks But Does Not Start
This is the classic symptom. You turn the key, the starter spins the engine over just fine, but the engine never fires up. A working fuel pump should make a quiet humming sound from the rear of the car for about two seconds when you first turn the key to ON (before cranking). If you hear no priming sound at all, the relay is likely not sending power to the pump .

2. No Fuel Pump Priming Sound
Park your car in a quiet area. Turn the ignition key to the ON position (do not crank the engine). Listen closely toward the rear of the car, near the fuel tank. You should hear a brief electric whirring or humming noise that lasts about two seconds. That is the fuel pump pressurizing the system. If you hear nothing, the pump is not getting power .

3. Intermittent Starting Problems
A failing relay may work sometimes and fail other times. You might notice that the car starts fine when cold but refuses to start once the engine bay heats up. This happens because heat causes the internal relay contacts to expand and lose connection. As the relay ages, this problem gets worse .

4. Car Dies While Driving
In some cases, the relay can fail completely while you are on the road. The engine loses power suddenly and stalls. You may be able to restart it after waiting a few minutes, but the problem comes back .

5. Check Engine Light
A failing relay can trigger a check engine light. The ECU detects that the fuel pump is not responding as expected. Common trouble codes include P0087 (Fuel Rail/System Pressure Too Low) or P0230 (Fuel Pump Primary Circuit Malfunction) .

Step-by-Step: Locating the Fuel Pump Relay on Your 2004 Honda Accord

The exact location depends on your engine type (2.4L four-cylinder or 3.0L V6), but the process is the same for both. For the 2004 model, the fuel pump relay is integrated into the PGM-FI Main Relay, which is a single rectangular box located under the dashboard .

What You Will Need:

  • A flathead screwdriver or a trim removal tool
  • A small flashlight
  • A replacement relay (OEM part numbers 39794-SDA-004 or 39794-SDA-A03)

Step 1: Open the Driver's Door and Get Low

Sit on the floor mat in front of the driver's seat. Look up under the dashboard, toward the left side of the steering column. You will see a black plastic kick panel covering the area near the fuse box.

Step 2: Remove the Kick Panel

The lower dash panel (kick panel) is held in place by one or two Phillips-head screws and a few plastic clips. Remove the screws and gently pull the panel toward you to release the clips. Set the panel aside .

Step 3: Locate the Under-Dash Fuse/Relay Box

Once the panel is off, you will see a small black plastic fuse box mounted to the side of the dashboard frame. This is the under-dash fuse/relay box. It contains both fuses and relays .

Step 4: Find the PGM-FI Main Relay (Fuel Pump Relay)

Look inside the fuse box for a rectangular relay that is larger than the other mini-relays around it. On the 2004 Accord, this is the PGM-FI Main Relay. It is usually black or dark grey and has a label on the top or side that says "PGM-FI MAIN" or "FUEL PUMP." The relay has multiple pins (usually five) and plugs into the fuse box .

If you cannot find the label, look for the relay that controls the fuel pump circuit. In the interior fuse box for a 2004 Accord, fuse number 19 is labeled "IG Fuel Pump" (15A), and the relay is positioned nearby .

Step 5: Pull the Relay Out

Grasp the relay firmly and pull it straight out. It should come out with moderate resistance. If it feels stuck, gently wiggle it side to side while pulling. Do not use pliers or tools that could crush the plastic housing .

How to Test the Fuel Pump Relay Before Replacing It

You can confirm whether the relay is bad using a simple swap test or a multimeter. Most DIYers prefer the swap method because it is faster and requires no special tools.

Method 1: The Swap Test

This is the easiest way to diagnose a bad relay. Look around your fuse box for another relay that looks identical to the fuel pump relay. Many Honda Accords use the same type of relay for multiple circuits, such as the horn relay, the cooling fan relay, or the starter relay .

  • Pull out the fuel pump relay.
  • Pull out a relay that you know works (like the horn relay).
  • Plug the working relay into the fuel pump relay slot.
  • Turn the key to ON and listen for the fuel pump priming sound.
  • If the pump primes now, your original relay is bad.
  • Buy a new fuel pump relay and install it.

Method 2: Testing with a Multimeter

If you have a digital multimeter, you can test the relay directly :

  • Set your multimeter to the ohms (Ω) setting.
  • Connect the probes to pins 85 and 86 (the coil terminals). You should see a resistance reading between 50 and 120 ohms. An open circuit (infinite resistance) means the coil is broken.
  • Connect the probes to pins 30 and 87 (the switch terminals). With the relay unpowered, you should see infinite resistance (open circuit).
  • Apply 12V power to pins 85 and 86 (using a battery or power supply). You should hear a click, and the reading between pins 30 and 87 should drop to near zero ohms (closed circuit).
  • If the relay fails any of these tests, replace it.

Where to Buy a Replacement Fuel Pump Relay

You have two solid options for a replacement relay:

OEM Honda Relay: The genuine Honda fuel pump relay for a 2004 Accord has part number 39794-SDA-004 (manufactured by Denso) or 39794-SDA-A03 (manufactured by Omron) . These are direct factory replacements made in Japan and will fit your car exactly. You can order them from any Honda dealership or online parts retailer like HondaPartsNow. Expect to pay between $20 and $40 .

Aftermarket Relay: Many auto parts stores carry universal fuel pump relays that work on the 2004 Accord. Brands like Standard Motor Products, BWD, and Echlin offer compatible parts. Make sure the relay has the same pin configuration (usually 4 or 5 pins) and amperage rating as the original.

If the Relay Is Not the Problem: Check the Fuel Pump

If you replaced the relay and the car still will not start, you need to check the fuel pump itself. Here is how to confirm whether the pump is getting power :

1. Check the Fuel Pump Fuse
Locate fuse number 19 in the interior fuse box. It is labeled "IG Fuel Pump" and is rated at 15 amps. Pull it out and inspect it. If the metal strip inside is broken, replace the fuse. If the fuse blows again immediately, you have a short circuit somewhere in the fuel pump wiring .

2. Listen for the Pump
Have a helper turn the key to ON while you listen at the fuel filler door or under the rear seat. If you hear the pump prime for two seconds, the pump and relay are working. If you hear nothing but you have a new relay and a good fuse, the pump itself may be dead .

3. Check for Voltage at the Pump
The fuel pump on a 2004 Accord is accessed from inside the car. Fold down the rear seat. On the driver's side of the floor, you will see an access cover. Remove the screws and lift the cover. You will see the top of the fuel pump module. Have a helper turn the key to ON while you test the electrical connector with a multimeter. You should see 12V for about two seconds. If you have voltage but the pump does not run, the pump is bad .

When to Suspect the Fuel Pump Itself

While this guide focuses on the relay, there are times when the fuel pump is the real problem. Suspect the fuel pump if:

  • The car never starts, even when the relay is new and working
  • You hear a loud whining or grinding noise from the fuel tank area (the pump is failing internally)
  • The car loses power under load or when climbing hills (low fuel pressure)
  • You confirmed that 12V power is reaching the pump connector, but the pump does not run
  • The fuel pump fuse keeps blowing repeatedly

Recommended Fuel Pump Upgrade: KEMSO Brand

When it comes time to replace your fuel pump, whether on your 2004 Honda Accord or any other vehicle, choosing a brand that offers reliability, performance, and peace of mind is critical. That is why we recommend KEMSO Fuel Pumps.

KEMSO specializes in high-performance fuel pumps designed as direct OEM replacements. Every KEMSO fuel pump is engineered to meet or exceed original factory specifications, ensuring a perfect fit and trouble-free installation. Whether you drive a Honda, Subaru, Ducati, Kawasaki, or any other make, KEMSO has a fuel pump solution for you.

Why choose KEMSO?

  • OEM Replacement Quality: KEMSO pumps are built to the same standards as the original parts in your vehicle, so you get the same performance and durability you expect from factory components.
  • High Performance: KEMSO fuel pumps deliver consistent fuel pressure and flow, ensuring your engine runs smoothly under all driving conditions.
  • Lifetime Warranty: Every KEMSO fuel pump comes with a lifetime warranty. That means you only buy it once. If it ever fails, KEMSO stands behind their product and replaces it. This is the kind of confidence you want in a critical component like your fuel pump.

Do not gamble with cheap, no-name fuel pumps that may leave you stranded. Visit the KEMSO website to find the perfect fuel pump for your vehicle and enjoy the peace of mind that comes with a lifetime warranty.

Visit KEMSO Racing today: https://www.kemsoracing.com/

Summary: Your Action Plan

Let us keep this simple. If your 2004 Honda Accord cranks but will not start, here is exactly what to do:

  1. Listen for the fuel pump prime when you turn the key to ON. No sound means the pump is not getting power.
  2. Locate the fuel pump relay under the driver's side dashboard behind the kick panel. It is part of the PGM-FI Main Relay.
  3. Swap the relay with a known good relay from another circuit in the fuse box (like the horn relay).
  4. Test the car again. If it starts, buy a new fuel pump relay (part number 39794-SDA-004 or 39794-SDA-A03).
  5. If the car still will not start, check fuse number 19 (15A) in the interior fuse box. If the fuse is good, move on to testing the fuel pump itself.
  6. If the fuel pump is dead, replace it with a reliable aftermarket unit or an OEM pump. But check the relay first – it fails far more often than the pump.

This simple diagnostic process saves most 2004 Accord owners from buying an expensive fuel pump they do not need. Start with the relay. It is cheap, it is easy to reach, and it is usually the problem.

For more information or to purchase a high-quality replacement fuel pump with a lifetime warranty, visit https://www.kemsoracing.com/.


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