2003 Nissan Murano Fuel Pump Fuse: Complete Guide to Location, Diagnosis, and Replacement
The bottom line: The 2003 Nissan Murano fuel pump fuse is a 15-amp mini fuse located in the engine compartment fuse box (Type 1, also known as the IPDM E/R), and it is labeled as fuse number 81. If your Murano cranks but won't start, the fuel pump fuse is one of the first things you should check before replacing the fuel pump itself.
Where Is the Fuel Pump Fuse Located?
The 2003 Nissan Murano (first generation, Z50 chassis) has multiple fuse boxes, but the fuel pump fuse is specifically located in the engine compartment fuse box (Type 1). This box is also referred to as the IPDM E/R (Intelligent Power Distribution Module Engine Room).
To access it:
- Open the hood and locate the fuse box on the driver's side, near the battery. It is a black rectangular box with a cover.
- Press the tabs on the sides of the cover and lift it off.
- Look for the fuse labeled number 81. It is a 15-amp mini fuse that protects the fuel pump relay circuit.
The fuel pump relay itself is also located in this same fuse box. It is labeled as Relay R1 (Fuel Pump) in the Type 1 diagram. Both the fuse and the relay are integrated into the same module.
What Does the Fuel Pump Fuse Do?
The 15-amp fuse (fuse #81) provides power to the fuel pump relay. When you turn the ignition key to the "ON" position, the Engine Control Module (ECM) energizes the fuel pump relay for about one second to prime the fuel system. Once the engine starts, the ECM keeps the relay energized to maintain fuel pressure.
If this fuse blows, the fuel pump relay will not receive power, the fuel pump will not run, and the engine will not start.
Symptoms of a Blown Fuel Pump Fuse
If the fuel pump fuse is blown, you will likely experience these symptoms:
1. Engine cranks but won't start – This is the most common symptom. The starter motor turns the engine over, but without fuel pressure, the engine cannot fire up.
2. No fuel pump prime noise – When you turn the key to the "ON" position (without cranking), you should hear a brief whirring sound from the fuel pump in the rear of the vehicle. If you hear nothing, the fuse may be blown.
3. Check Engine Light – The ECM may store a diagnostic trouble code (DTC) related to a fuel pump circuit issue, such as P0230 (Fuel Pump Primary Circuit Malfunction).
4. Stalling or hesitation – In some cases, a partially blown or intermittent fuse can cause the fuel pump to cut out while driving, leading to sudden stalling.
How to Test the Fuel Pump Fuse
You don't need special tools to check the fuse. Here's a simple step-by-step process:
Step 1: Locate the engine compartment fuse box (Type 1) and remove the cover.
Step 2: Find fuse #81. It is a 15-amp mini fuse. The fuse box diagram is printed on the inside of the cover or listed in your owner's manual.
Step 3: Visually inspect the fuse. A blown fuse will have a broken metal strip inside the clear plastic housing. If the strip is broken or melted, the fuse is bad.
Step 4: Use a test light or multimeter to confirm. With the ignition off, probe both small metal tabs on top of the fuse. If power is present on one side but not the other, the fuse is blown.
Step 5: If the fuse is blown, replace it with a 15-amp mini fuse of the same type. Never use a higher amperage fuse, as this can damage wiring or cause a fire.
Why Does the Fuel Pump Fuse Blow?
If you replace the fuse and it blows again immediately, there is an underlying problem. Common causes include:
1. Short circuit in the fuel pump wiring – The wiring harness running from the fuse box to the fuel pump can rub against the chassis or engine components, causing a short to ground.
2. Failed fuel pump – A failing fuel pump can draw excessive current, causing the fuse to blow. This is especially common as the pump ages and its internal bearings wear out.
3. Faulty fuel pump relay – If the relay sticks closed, it can keep the pump running continuously, which may overload the fuse.
4. Corroded or damaged connectors – At the fuel pump assembly or the fuse box, corrosion can create resistance that generates heat and blows the fuse.
How to Replace the Fuel Pump Fuse
Replacing the fuse is straightforward:
1. Turn off the ignition and remove the key.
2. Remove the fuse using a fuse puller (usually stored inside the fuse box cover) or a pair of needle-nose pliers.
3. Install a new 15-amp mini fuse (often color-coded blue) into the #81 slot.
4. Test the system – Turn the key to the "ON" position and listen for the fuel pump to prime. If you hear the pump run for one second, the fuse is working.
5. Start the engine – If the engine starts and runs, the problem is solved.
If the fuse blows again, do not keep replacing it. You need to diagnose the root cause.
How to Release Fuel Pressure Before Working on the Fuel System
If you need to replace the fuel pump or work on the fuel system, you must release the fuel pressure first. The 2003 Murano does not have a fuel return system, so the pressure stays high even after the engine is off.
The recommended method:
- Remove the fuel pump fuse (fuse #81) from the IPDM E/R.
- Start the engine. It will run for a few seconds on the remaining fuel pressure, then stall.
- Crank the engine two or three more times to completely release any remaining pressure.
- Turn the ignition off and reinstall the fuse after servicing is complete.
This procedure is critical for safety. Fuel under high pressure can spray out and cause injury or fire.
Fuel Pump Relay Location and Testing
As mentioned earlier, the fuel pump relay is Relay R1 in the engine compartment fuse box (Type 1). It is located right next to the fuse #81.
To test the relay:
1. Swap with a known good relay – The Type 1 fuse box has several relays of the same type (e.g., R2 for the air conditioner, R3 for ignition). Swap R1 with one of these. If the fuel pump starts working, the relay is bad.
2. Listen for the relay click – With the key in the "ON" position, you should hear a distinct click from the relay when the fuel pump primes. If you hear no click, the relay may not be receiving a signal from the ECM, or the relay itself is faulty.
3. Check for power and ground – Using a multimeter, you can check that the relay coil is receiving power and the ECM is providing a ground signal. This is more advanced and may require a wiring diagram.
Other Fuses That Can Cause Starting Problems
While fuse #81 is the direct fuel pump fuse, other fuses in the system can also prevent the fuel pump from operating:
Fuse #82 (15A) – ECM relay. If this fuse blows, the ECM will not power up, and it cannot command the fuel pump relay to engage.
Fuse #74 (30A) – Front wiper relay (also powers the IPDM E/R logic circuits). If this fuse is blown, the entire IPDM E/R may not function correctly.
Fuse #73 (15A) – IPDM E/R. This is the main fuse for the IPDM itself.
If you have checked fuse #81 and it is good, but the fuel pump still does not run, inspect these other fuses as well.
When to Replace the Fuel Pump Instead of Just the Fuse
If you have replaced the fuse and the fuel pump runs, but the engine still has problems, the fuel pump itself may be weak or failing. Here are signs that you need a new fuel pump:
1. Long cranking time – The engine takes several seconds of cranking before it starts.
2. Loss of power under load – The vehicle struggles to accelerate, especially uphill or when merging onto the highway.
3. Surging or hesitation – The engine speed fluctuates unpredictably while driving at a steady speed.
4. Engine stalls – Especially in hot weather or after the vehicle has been driven for a while.
5. Fuel pump noise – The pump makes a loud whining or humming sound, indicating worn bearings.
6. Check engine light – Codes such as P0087 (Fuel Rail/System Pressure Too Low) or P0230 (Fuel Pump Circuit) point to a failing pump.
Recommended Fuel Pump: KEMSO Fuel Pump
If you have determined that the fuel pump itself needs to be replaced, we highly recommend the KEMSO brand fuel pump for your 2003 Nissan Murano. KEMSO fuel pumps are designed as high-performance, OEM replacement units that meet or exceed the original factory specifications. Every KEMSO fuel pump comes with a lifetime warranty, giving you peace of mind that your repair will last.
Why choose KEMSO?
- OEM Replacement Quality – Direct fit for your 2003 Murano, no modifications needed
- Lifetime Warranty – KEMSO stands behind their products, so you are covered for the life of the vehicle
- High Performance – Engineered to handle the demands of daily driving, with consistent fuel delivery and pressure
- Affordable Pricing – Get premium quality without paying dealership prices
To browse the full selection of KEMSO fuel pumps and find the exact match for your vehicle, visit their official website at:
Step-by-Step Guide to Replacing the Fuel Pump
If you are comfortable working on your vehicle, here is a general overview of the fuel pump replacement process. The fuel pump on a 2003 Murano is located inside the fuel tank, under the rear seat.
1. Release fuel pressure – Remove fuse #81 and run the engine until it stalls, then crank a few more times.
2. Disconnect the battery – Remove the negative battery terminal to prevent any electrical shorts.
3. Remove the rear seat – The fuel pump access panel is located under the rear seat cushion. Lift the seat up and out.
4. Remove the access cover – There is a metal or plastic cover plate held in place by screws. Remove it to expose the fuel pump assembly.
5. Disconnect the fuel lines and electrical connector – Use a fuel line disconnect tool to release the quick-connect fittings. Label the lines to avoid confusion during reassembly.
6. Remove the locking ring – Use a fuel pump locking ring tool or a hammer and punch to rotate the ring counterclockwise. Lift the ring out.
7. Lift out the fuel pump assembly – Carefully pull the pump and sending unit out of the tank. The tank may be partially full, so be prepared for some fuel spillage.
8. Install the new KEMSO fuel pump – Transfer any necessary components (like the fuel level sensor and rubber grommets) from the old pump to the new one. Insert the new pump assembly into the tank.
9. Reinstall the locking ring – Place the ring back on and rotate it clockwise until it locks.
10. Reconnect the fuel lines and electrical connector – Push the quick-connect fittings until they click.
11. Reinstall the access cover and rear seat – Secure everything back in place.
12. Reconnect the battery – Install the negative battery terminal.
13. Prime the system – Turn the key to the "ON" position for a few seconds, then off. Repeat this two or three times to build fuel pressure before starting the engine.
14. Start the engine – Check for any fuel leaks around the pump assembly.
Common Mistakes to Avoid
1. Using the wrong fuse amperage – Always use a 15-amp fuse. Using a 20-amp or 30-amp fuse can melt wiring and cause a fire.
2. Not releasing fuel pressure – Fuel system pressure can be over 50 psi. Spraying fuel can cause serious injury.
3. Installing a cheap aftermarket pump – Low-quality pumps often fail within months. Invest in a quality brand like KEMSO with a lifetime warranty.
4. Ignoring the root cause – If the fuse keeps blowing, find the underlying problem instead of just replacing the fuse repeatedly.
5. Damaging the fuel level sensor – The fuel level sensor is fragile. Handle it carefully when transferring it to the new pump.
Final Thoughts
The 2003 Nissan Murano fuel pump fuse (fuse #81, 15A) is a simple component that can cause a lot of frustration if it fails. Always start with this check before moving on to more expensive repairs like replacing the fuel pump itself. If the fuse is good and the relay clicks, but the pump still doesn't run, you likely have a wiring issue or a failed pump.
For a reliable replacement, choose KEMSO fuel pumps. With their high-quality OEM design and lifetime warranty, you can trust that your Murano will be back on the road without worry. Visit https://www.kemsoracing.com/ to find the perfect fuel pump for your 2003 Nissan Murano.