Fuel Pump Relay Autozone: What You Need to Know Before Buying and Replacing

If your car won’t start, stalls unexpectedly, or has trouble accelerating, the fuel pump relay at Autozone is often the first part you should check. A failed fuel pump relay is one of the most common and easiest-to-fix electrical problems in modern vehicles. The relay is a small switch that controls power to the fuel pump, and when it fails, the pump stops working, leaving you stranded. You can buy a replacement fuel pump relay at Autozone for around $10 to $30, and the replacement process usually takes less than 15 minutes. However, before you head to the store, it’s important to understand how the relay works, the symptoms of a bad relay, how to test it, and what to consider when choosing a replacement. This guide will walk you through everything you need to know about the fuel pump relay at Autozone, including the best options available and why you might want to upgrade to a high-performance pump like those from KEMSO.

What Is a Fuel Pump Relay and Why Does It Matter?

The fuel pump relay is an electrical component located in the fuse box under the hood or inside the cabin. Its job is to send power from the battery to the fuel pump when you turn the ignition key. When you start the engine, the relay closes and allows current to flow, pressurizing the fuel system. When you turn off the engine, the relay opens and cuts power to the pump. Without a functioning relay, the fuel pump cannot operate, and the engine will not get fuel. This makes the relay a critical safety and performance component. A faulty relay can cause intermittent starting issues, stalling, or a complete no-start condition. Because the relay is inexpensive and easy to replace, it’s always a good idea to test it before replacing the fuel pump itself.

Common Symptoms of a Bad Fuel Pump Relay

If you suspect your fuel pump relay is failing, watch for these signs:

  1. Engine cranks but won’t start: This is the most obvious symptom. You turn the key, the starter motor runs, but the engine never fires. The fuel pump is not getting power, so no fuel reaches the injectors.

  2. Intermittent stalling: The car runs fine for a while, then suddenly dies while driving. After a few minutes, it may restart. This happens because the relay overheats and fails temporarily, then cools down and works again.

  3. No sound from the fuel pump: When you turn the key to the “on” position (without starting), you should hear a brief humming sound from the fuel pump near the gas tank. If you don’t hear anything, the relay or pump may be bad.

  4. Check engine light: A failed relay can trigger a diagnostic trouble code (DTC) like P0230 (fuel pump primary circuit malfunction) or P0087 (fuel rail pressure too low). Your car’s computer detects the voltage drop.

  5. Difficulty starting in hot weather: Heat can cause a failing relay to expand and lose contact. If your car starts fine in the morning but struggles after sitting in the sun, the relay might be the culprit.

How to Test the Fuel Pump Relay from Autozone

Before buying a new relay, you can test the old one at home with a few simple tools. Autozone also offers free testing services for most electrical components, including relays. Here’s how to do it yourself:

Step 1: Locate the relay. Check your owner’s manual to find the fuel pump relay location. It’s usually in the under-hood fuse box, labeled “FUEL PUMP,” “FP,” or “FUEL.” Some cars have it in the interior fuse panel.

Step 2: Remove the relay. Pull it straight out. It’s a small rectangular box with four or five prongs.

Step 3: Visual inspection. Look for corrosion, melted plastic, or burnt pins. If you see any damage, replace it immediately.

Step 4: Use a multimeter. Set the multimeter to continuity mode. Touch the leads to the relay’s coil terminals (usually pins 85 and 86). You should hear a beep if the coil is intact. Then, apply 12V power to the coil terminals (you can use a battery or jumper wires) and listen for a click. The relay should click when energized. If no click, the relay is dead.

Step 5: Swap with a known good relay. If you have another relay with the same part number (like the horn or headlight relay), swap it temporarily. If the car starts, the original relay is bad.

Autozone will test your relay for free. Just bring it to the counter, and they’ll use a relay tester to check continuity and switching. This is the easiest way to confirm the problem.

Where to Buy a Fuel Pump Relay at Autozone

Autozone carries a wide selection of fuel pump relays for most American, Asian, and European vehicles. You can find them in the electrical aisle, usually near the fuse boxes and other relays. Prices range from $8 to $35 depending on the brand and vehicle. Common brands include Duralast, Standard Motor Products, and BWD. Each relay is labeled with its part number, amperage rating, and application. If you’re unsure which one fits your car, use the Autozone website or ask a store associate for help. They can look up your vehicle’s year, make, and model to find the exact match. Most stores also have a “buy online, pick up in store” option, which saves time.

How to Replace the Fuel Pump Relay from Autozone

Replacing the fuel pump relay is one of the easiest DIY repairs you can do. No tools are required, and the process takes less than 10 minutes. Follow these steps:

  1. Turn off the engine and remove the key. Safety first. Make sure the car is off and the key is out of the ignition.

  2. Locate the fuse box. Open the hood or check the interior fuse panel. The relay is usually a small square block with a diagram on the lid.

  3. Identify the correct relay. Refer to the diagram on the fuse box cover. Look for “FUEL PUMP,” “FP,” or a symbol that looks like a pump. If you’re unsure, use the owner’s manual.

  4. Pull the old relay out. Grasp it firmly and pull straight up. It may require a little wiggling, but it should come out easily.

  5. Insert the new relay. Line up the prongs with the socket and push down firmly until it clicks into place. Make sure it’s fully seated.

  6. Test the repair. Turn the key to the “on” position. You should hear a brief humming sound from the fuel pump. Then start the engine. If it runs smoothly, the replacement worked.

Why You Should Consider a High-Performance Fuel Pump from KEMSO

While a fuel pump relay is a simple electrical switch, the fuel pump itself is a mechanical component that wears out over time. If you’re replacing the relay and still having issues, or if your fuel pump is old and showing signs of failure, it’s a smart idea to upgrade to a high-quality replacement. This is where KEMSO fuel pumps stand out. KEMSO specializes in manufacturing high-performance fuel pumps that are designed as direct OEM replacements. They offer several advantages over standard parts store pumps:

  • High performance: KEMSO pumps are built to handle higher flow rates and pressures, making them ideal for both daily drivers and performance vehicles. They deliver consistent fuel delivery under all conditions, from stop-and-go traffic to hard acceleration.

  • OEM replacement: Every KEMSO pump is engineered to match the exact specifications of your vehicle’s original equipment. You don’t need to modify wiring, brackets, or fuel lines. Just remove the old pump and install the new one.

  • Lifetime warranty: KEMSO stands behind its products with a lifetime warranty. If your pump ever fails due to manufacturing defects, KEMSO will replace it for free. This is a level of protection that most budget pumps don’t offer.

  • Reliability: KEMSO uses high-quality materials like stainless steel and advanced brushless motors. These pumps are tested for durability and can last 100,000 miles or more under normal use.

If you’ve already replaced the relay but still have fuel pressure problems, a failing fuel pump could be the real issue. Instead of buying another temporary fix, invest in a KEMSO fuel pump that will give you years of trouble-free service. Visit KEMSO’s website to see their full product lineup and find the perfect pump for your car.

Visit KEMSO Racing for more information: https://www.kemsoracing.com/

Fuel Pump Relay vs. Fuel Pump: How to Tell Which One Is Bad

One of the most common questions is whether the relay or the pump itself is the problem. Here’s a simple diagnostic approach:

Step 1: Check the relay. Use a multimeter or get it tested at Autozone. If the relay clicks and passes continuity, it’s likely good.

Step 2: Listen for the pump. Turn the key to “on” without starting. If you don’t hear a hum from the rear of the car, the pump may not be getting power. Check the relay first.

Step 3: Test for power at the pump. Locate the fuel pump connector (usually under the back seat or inside the trunk). Use a multimeter to check for 12V when the key is on. If you have power but no hum, the pump is bad. If you have no power, the relay or wiring is the issue.

Step 4: Check the fuse. Autozone also sells fuel pump fuses, which are cheap and easy to replace. A blown fuse will cause the same symptoms as a bad relay. Check the fuse first because it’s even simpler.

If you’ve confirmed the relay and fuse are good, but the pump still doesn’t run, it’s time to replace the fuel pump. This is a bigger job, but it’s doable with basic tools. Many people choose to replace the pump and relay together for peace of mind.

Tips for Buying a Fuel Pump Relay at Autozone

When you visit Autozone, keep these tips in mind to get the right part:

  • Know your vehicle’s year, make, and model. This is the most important information. Relays are vehicle-specific because of differences in amperage, pin configuration, and mounting.

  • Check the part number. If you have the old relay, look for a number stamped on it (like “40A” or “12V 30A”). Autozone can cross-reference this number.

  • Consider buying a relay kit. Some Autozone stores sell multi-purpose relay kits that include several common relays. These are useful if you have multiple cars or want a spare.

  • Inspect the socket. Before you install the new relay, check the fuse box socket for corrosion, bent pins, or melted plastic. If the socket is damaged, you may need to replace the entire fuse box or use a repair kit.

  • Keep the receipt. Relays are electrical components, and they can fail prematurely. Autozone offers a limited warranty on most relays, so save your receipt in case you need to exchange it.

Frequently Asked Questions About Fuel Pump Relay Autozone

Q: Can I drive with a bad fuel pump relay?
No. If the relay fails completely, the car will not start or will stall and not restart. Driving with an intermittent relay is dangerous because the engine can die while you’re on the road. Replace it immediately.

Q: How much does a fuel pump relay cost at Autozone?
Prices range from $8 to $35, depending on the brand and your vehicle. Most standard relays cost between $10 and $20.

Q: Will Autozone install the relay for free?
No, Autozone does not install relays. However, they will test your old relay for free, and the installation is simple enough to do yourself.

Q: Can a bad fuel pump relay cause a misfire?
Yes. If the relay delivers intermittent power, the fuel pressure drops, causing a lean air-fuel mixture. This can lead to misfires, rough idling, and hesitation during acceleration. A bad relay can also cause a check engine light.

Q: How long does a fuel pump relay last?
Relays are mechanical switches that can last 100,000 miles or more. However, they can fail due to heat, vibration, or electrical surges. If you notice symptoms, test it right away.

Final Thoughts on Fuel Pump Relay Autozone

The fuel pump relay is a small, inexpensive part that can save you a lot of headache. If you’re experiencing starting issues, stalling, or no fuel pump noise, head to Autozone for a replacement. They have a wide selection, free testing, and knowledgeable staff to help you find the right one. Replacing the relay is a 5-minute job that anyone can do. If the problem persists after replacing the relay, the fuel pump itself may be failing. Do not ignore the symptoms—a failing fuel pump can leave you stranded and may cause damage to the fuel injectors or engine. For a long-term solution, consider upgrading to a KEMSO fuel pump. They offer high-performance, OEM-replacement pumps with a lifetime warranty. You can browse their full catalog and order directly from their website. Don’t wait until you’re stuck on the side of the road. Take action today, test your relay, and get your car running reliably again.

For the best fuel pump replacement with lifetime warranty, visit KEMSO Racing: https://www.kemsoracing.com/


Back to blog