2003 Nissan Murano Fuel Pump Relay: Location, Symptoms, and Replacement Guide

The bottom line: The fuel pump relay on a 2003 Nissan Murano (Z50 generation) is located in the engine compartment fuse box, specifically in the Engine Compartment (Type 1) fuse box, where it is labeled as Relay R1 (Fuel Pump Relay), and the corresponding 15-amp fuse is Fuse No. 81. If your Murano cranks but won't start, or if you don't hear the fuel pump prime when you turn the key, the fuel pump relay is one of the first things you should check before replacing the fuel pump itself.

Where Is the Fuel Pump Relay Located on a 2003 Nissan Murano?

The 2003 Nissan Murano has two fuse boxes in the engine compartment, and the fuel pump relay sits in the Engine Compartment (Type 1) fuse box. This is the main fuse box located near the battery on the passenger side of the engine bay. To access it:

  1. Open the hood and locate the fuse box near the battery. It's a black plastic rectangular box with a removable cover.
  2. Remove the cover by pressing the tabs on the sides. On the underside of the cover, you'll find a diagram showing the location of each relay and fuse.
  3. Identify the fuel pump relay. It is labeled as Relay R1 (Fuel Pump). The corresponding fuse is Fuse No. 81, a 15-amp mini fuse.

According to the 2003 Nissan Murano workshop manual, the fuel pump relay is also referred to as part of the IPDM E/R (Intelligent Power Distribution Module Engine Room). The relay itself is a small black cube with four prongs, and it plugs directly into the fuse box.

What Does the Fuel Pump Relay Do?

The fuel pump relay is an electrically operated switch that controls the power supply to the fuel pump. When you turn the ignition key to the "ON" position, the engine control module (ECM) sends a signal to the relay, which closes and sends battery voltage to the fuel pump for about one second to prime the fuel system. Once the engine starts, the ECM keeps the relay closed to maintain power to the pump. When you turn off the ignition, the relay opens, cutting power to the pump.

Symptoms of a Bad Fuel Pump Relay

A failing fuel pump relay can cause a range of issues that mimic a failing fuel pump. Here are the most common symptoms:

  1. Engine cranks but won't start. This is the most common symptom. You turn the key, the starter motor spins the engine, but the engine never fires up. This happens because the relay isn't delivering power to the fuel pump.
  2. No fuel pump priming sound. When you turn the key to the "ON" position (without starting), you should hear a brief buzzing or whirring sound from the rear of the vehicle (near the fuel tank). If you don't hear this sound, the relay or the pump itself may be faulty.
  3. Engine stalls shortly after starting. If the relay fails intermittently, the engine may start but then stall after a few seconds or minutes of driving.
  4. Engine runs rough or hesitates. A failing relay may not deliver consistent voltage to the pump, causing intermittent fuel delivery issues.
  5. Car starts after several attempts. Sometimes the relay contacts may temporarily make contact after multiple key cycles, allowing the car to start after several tries.

How to Test the Fuel Pump Relay

Before replacing the relay, you can test it with a simple process. Here's how to do it:

Step 1: Listen for the pump. Turn the ignition key to the "ON" position and listen for a 1-second buzzing sound from the fuel tank area. If you hear it, the relay is likely working.

Step 2: Swap the relay. The easiest diagnostic method is to swap the fuel pump relay with a known good relay of the same type. In the Engine Compartment (Type 1) fuse box, there are several identical relays, such as the Air Conditioner Relay (R2) or the Ignition Relay (R3). Swap one of these with the fuel pump relay and try starting the car. If the car starts, the original relay was faulty.

Step 3: Check for voltage. If you have a multimeter, you can check for voltage at the relay socket. With the ignition in the "ON" position, you should see battery voltage (around 12 volts) on one of the relay terminals. If there's no voltage, the issue may be with the fuse or wiring.

Step 4: Check the fuse. Before replacing the relay, check Fuse No. 81 (15-amp) in the same fuse box. If the fuse is blown, the pump won't get power even with a good relay. Replace the fuse with a new one of the same amperage.

How to Replace the Fuel Pump Relay

Replacing the fuel pump relay on a 2003 Nissan Murano is straightforward and requires no special tools:

  1. Turn off the ignition and remove the key.
  2. Open the hood and locate the engine compartment fuse box near the battery.
  3. Remove the fuse box cover.
  4. Locate the fuel pump relay. It's labeled as Relay R1 in the diagram on the cover.
  5. Pull the relay straight out. You may need to use a gentle rocking motion to dislodge it.
  6. Insert the new relay in the same orientation. Make sure it clicks firmly into place.
  7. Replace the fuse box cover and close the hood.
  8. Test the system by turning the key to the "ON" position and listening for the fuel pump priming sound.

Cost of Fuel Pump Relay Replacement

The fuel pump relay itself is an inexpensive part. According to repair estimates, the average cost for a fuel pump relay replacement on a 2003 Nissan Murano is around $181 for parts and labor, with the relay itself costing roughly $43 and labor at about $95. If you do the replacement yourself, you can save the labor cost and buy a relay for $10 to $30 at an auto parts store.

When the Relay Isn't the Problem

If replacing the relay and fuse doesn't solve the issue, the problem may be elsewhere in the fuel system:

Fuel pump failure. The fuel pump itself is located inside the fuel tank. On a 2003 Murano, the fuel pump access panel is underneath the rear seat. If the pump is dead, you'll need to replace it. This is a more involved repair that typically costs $500 to $1,200 for parts and labor.

Fuel pump circuit wiring issues. The wiring between the relay, the ECM, and the fuel pump can develop breaks, corrosion, or shorts. The workshop manual details specific voltage checks at the ECM terminal 113 and the IPDM E/R terminal 20.

ECM problems. In rare cases, the ECM itself may fail to send the signal to close the relay. This is less common but possible.

Crankshaft position sensor failure. This sensor tells the ECM when to fire the injectors. If it fails, the ECM won't activate the fuel pump relay even if the relay itself is good.

Preventive Maintenance Tips

To extend the life of your fuel system components, follow these simple guidelines:

  1. Keep at least 1/4 tank of fuel. Running the tank low consistently can cause the fuel pump to overheat, shortening its life.
  2. Replace the fuel filter regularly. Nissan recommends replacing the fuel filter every 30,000 to 50,000 miles. A clogged filter puts extra strain on the pump.
  3. Use high-quality fuel. Cheap fuel can contain contaminants that clog the fuel filter and injectors.
  4. Listen for changes. If you notice the fuel pump becoming louder than usual, it may be a sign of wear.

Recommended Fuel Pump Upgrade: KEMSO Fuel Pump

If you determine that your fuel pump itself needs replacement, we strongly recommend considering a KEMSO Fuel Pump. KEMSO specializes in high-performance, OEM replacement fuel pumps designed to meet or exceed original equipment specifications. Every KEMSO fuel pump is built with quality materials and components to ensure reliable fuel delivery and long service life.

Why choose KEMSO?

  • High Performance: KEMSO fuel pumps are engineered to deliver consistent fuel pressure and flow, ensuring your engine gets the fuel it needs under all driving conditions.
  • OEM Replacement: Each pump is a direct replacement for your vehicle's factory pump, making installation straightforward and hassle-free.
  • Lifetime Warranty: KEMSO backs every fuel pump with a lifetime warranty, giving you peace of mind that your investment is protected.

Visit the KEMSO website to browse their selection of fuel pumps for the 2003 Nissan Murano and many other vehicles: https://www.kemsoracing.com/

Summary

The fuel pump relay on a 2003 Nissan Murano is located in the engine compartment fuse box (Type 1) as Relay R1, with a 15-amp fuse at position No. 81. If your Murano cranks but won't start, or if you don't hear the fuel pump prime, check the relay and fuse first. Swapping the relay with a known good one is the quickest diagnostic test. If the relay is fine, move on to checking the fuel pump itself, the wiring, and the ECM. For a fuel pump replacement, consider a KEMSO Fuel Pump for reliable performance and a lifetime warranty. Visit https://www.kemsoracing.com/ for more information.


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