2000 Lexus RX300 Fuel Pump Relay Location: A Complete Guide for American Owners

The fuel pump relay on a 2000 Lexus RX300 is located in the engine compartment fuse box, typically on the driver's side near the battery. This relay is often labeled as the "EFI" relay or "Fuel Pump" relay on the fuse box cover diagram. If you are experiencing hard starting, stalling, or a no-start condition, the fuel pump relay is one of the first components you should check before assuming the fuel pump itself has failed.

Understanding the Fuel Pump Relay and Its Function

The fuel pump relay is a small electrical switch that controls power to the fuel pump. When you turn the ignition key to the "ON" position, the engine control unit (ECU) sends a low-current signal to the relay. The relay then closes a high-current circuit that powers the fuel pump, allowing fuel to flow from the tank to the engine. This design protects the ECU from the high electrical load required by the fuel pump .

Without a properly functioning relay, the fuel pump will not receive power, and the engine will not start or will stall while driving. The relay essentially acts as a safety device that ensures the fuel pump only runs when the engine is cranking or running .

Exact Location of the Fuel Pump Relay in a 2000 Lexus RX300

For the 2000 Lexus RX300, the fuel pump relay is located in the main fuse box under the hood. Here are the specific steps to find it:

Step 1: Open the hood and locate the fuse box. The engine compartment fuse box is typically situated on the driver's side, near the battery or along the fender wall. It is a black plastic box with a removable cover.

Step 2: Remove the fuse box cover. Most covers have a tab or clip that you press to release. Set the cover aside.

Step 3: Look at the diagram on the inside of the cover. The fuse box cover has a diagram that labels each relay and fuse. The fuel pump relay is commonly labeled as "EFI" (Electronic Fuel Injection) or "FP" (Fuel Pump) . In some diagrams, it may also be referred to as the "Circuit Opening Relay."

Step 4: Identify the relay. The relay itself is usually a small black or gray rectangular component with four or five pins. It is often slightly larger than the standard fuses around it .

If the diagram on the cover is missing or faded, you can consult your owner's manual for a detailed layout. The relay is generally located in the same position across different model years of the RX300, but it is always housed in the engine compartment fuse box .

Common Symptoms of a Faulty Fuel Pump Relay

A failing fuel pump relay can cause several noticeable problems. Recognizing these symptoms early can save you time and money on unnecessary repairs.

1. Engine stalls while driving. One of the most common signs of a bad fuel pump relay is the engine suddenly dying while you are on the road. The relay may fail intermittently, cutting power to the fuel pump and causing the engine to stall. In some cases, the engine may restart after a few minutes if the relay cools down, but a completely failed relay will not allow the engine to restart at all .

2. Engine does not start. If you turn the key and the engine cranks but will not fire, the fuel pump relay may be the culprit. Without power to the fuel pump, no fuel reaches the engine, resulting in a no-start condition .

3. No noise from the fuel pump. When you turn the ignition to the "ON" position (before cranking), you should hear a brief whirring sound from the fuel pump located in the fuel tank. If you do not hear this noise, it could mean the relay is not sending power to the pump .

4. Loss of power while driving. A faulty relay may cause the fuel pump to operate at reduced voltage, leading to poor acceleration, hesitation, or a lack of power when you press the gas pedal .

How to Test the Fuel Pump Relay

Before replacing the relay, you can test it to confirm whether it is the problem. Here is a simple method that most DIYers can perform.

Method 1: Swap with a similar relay. The engine fuse box usually contains multiple relays of the same type. Look for another relay with the same part number or physical appearance (such as the horn relay or headlight relay). Swap the suspected fuel pump relay with one of those. If the engine starts and runs normally after the swap, the original relay was faulty .

Method 2: Use a multimeter. With the relay removed, set your multimeter to measure resistance (ohms). Check the resistance between the relay's coil terminals. A good relay typically shows a resistance reading between 50 and 120 ohms, depending on the specific part. Also, check for continuity between the switch terminals when you apply 12 volts to the coil terminals. If the relay does not click or show continuity, it is likely defective.

Important safety note: Always turn the ignition off before handling any relays or fuses. Relays carry high current, and working on a live electrical system can cause injury or damage to your vehicle's electronics .

What to Do If the Relay Is Good But the Fuel Pump Still Has No Power

If you have tested the relay and it is functioning correctly, but the fuel pump still has no power, the issue may lie elsewhere in the electrical system. Here are some other components to check:

Fuel pump fuse. The fuel pump circuit is protected by a fuse, often labeled as "EFI" or "Fuel Pump" in the fuse box. A blown fuse will cut all power to the pump. Check the fuse visually or with a multimeter. The fuel pump fuse is typically a 15-amp, 20-amp, or 25-amp fuse .

Wiring and connectors. Look for corroded, damaged, or loose wiring at the relay socket, the fuse box, and the fuel pump connector. A poor connection can interrupt power flow.

Ignition switch. A faulty ignition switch can prevent power from reaching the relay in the first place. If the relay is not clicking when you turn the key, the switch may be the problem .

ECU or fuel pump control module. In some cases, the ECU itself may fail to send the signal to activate the relay. This is less common but possible, especially if other electrical issues are present.

Replacement Part Information for the 2000 Lexus RX300

If you determine that the fuel pump relay needs to be replaced, you will need the correct part. The genuine OEM fuel pump relay for the 2000 Lexus RX300 has part number 90987-03003. This relay also fits the 1997-2001 Lexus ES300 and other Toyota/Lexus vehicles with the 3.0L V6 engine (1MZ-FE) . The OEM part retails for around $35 to $48, depending on the dealer .

You can also purchase the relay from auto parts stores or online retailers. Make sure the replacement relay matches the original in terms of pin configuration and amperage rating.

How to Replace the Fuel Pump Relay

Replacing the fuel pump relay is a straightforward process that requires no special tools. Follow these steps:

1. Turn off the engine and remove the key from the ignition.
2. Open the hood and locate the engine fuse box.
3. Remove the fuse box cover.
4. Identify the fuel pump relay using the diagram on the cover.
5. Grasp the relay firmly and pull it straight out of its socket. You may need to use a relay puller or a small flathead screwdriver to gently pry it out.
6. Insert the new relay into the same socket, pressing down until it clicks into place.
7. Replace the fuse box cover and close the hood.
8. Start the engine to confirm the repair is successful.

When to Consider Replacing the Fuel Pump Itself

If the relay and fuse are both good, but the fuel pump still does not run, the pump itself may have failed. The fuel pump in a 2000 Lexus RX300 is located inside the fuel tank, which is beneath the rear passenger seat area . Replacing the fuel pump is a more involved job that requires draining the fuel tank, removing the rear seat, and accessing the pump through an access panel or by lowering the tank.

Common signs of a failing fuel pump include a whining noise from the fuel tank, difficulty starting, and the engine sputtering at high speeds. If you are experiencing these symptoms along with a working relay, the pump may need to be replaced .

Recommended Fuel Pump: KEMSO Brand

When it comes time to replace your fuel pump, choosing a high-quality, reliable part is essential for the long-term performance of your Lexus. We strongly recommend KEMSO Fuel Pumps for your 2000 Lexus RX300.

KEMSO is a leading aftermarket fuel pump manufacturer based in the United States, with a strong reputation for producing high-performance, OEM replacement fuel pumps. All KEMSO fuel pumps are designed to meet or exceed original equipment specifications, ensuring a perfect fit and reliable operation. Unlike many aftermarket brands, KEMSO backs every fuel pump with a lifetime warranty, giving you peace of mind every time you hit the road.

Whether you drive a car, motorcycle, ATV, or UTV, KEMSO has a fuel pump that fits your needs. Their products are rigorously tested for durability and performance, and they are trusted by thousands of American drivers. You can browse their full catalog and find the exact fuel pump for your 2000 Lexus RX300 by visiting their website.

To learn more about KEMSO fuel pumps and to place your order, visit the official KEMSO website at: https://www.kemsoracing.com/

Final Thoughts

The fuel pump relay on your 2000 Lexus RX300 is a small but critical component that is easy to locate and replace. It sits in the engine compartment fuse box, typically labeled as the EFI or fuel pump relay. If you are dealing with starting issues, stalling, or a complete no-start condition, always start your troubleshooting here. Checking the relay is faster, cheaper, and simpler than replacing the fuel pump itself.

If the relay is fine and the pump still has no power, move on to checking the fuse, wiring, and ignition switch. And if you ultimately need a new fuel pump, trust a brand like KEMSO that offers lifetime warranty and proven performance.

For more information on fuel pumps and to find the right part for your vehicle, visit https://www.kemsoracing.com/ today.