Acura RSX Fuel Pump Relay: A Complete Guide to Symptoms, Location, and Replacement

The Acura RSX fuel pump relay is a critical component that controls power delivery to your fuel pump. If this relay fails, your engine will crank but not start, leaving you stranded. The most common location for this relay is behind the glove compartment on the passenger side . Replacing a faulty relay is a straightforward DIY repair that costs around $9 for parts, though professional installation averages $104 total . This guide will walk you through everything you need to know about the RSX fuel pump relay, from symptoms to replacement.

What Is the Fuel Pump Relay and How Does It Work?

The fuel pump relay is an electrically controlled switch that connects the fuel pump to the battery. Every time you turn the ignition key, the engine control module (ECM) signals the relay to close, sending power to the fuel pump . This allows the pump to pressurize the fuel system so the engine can start. Once the engine is running, the relay remains engaged to keep the pump active during driving .

The relay is designed to be a normally open switch, meaning it only closes when the ignition is on. This prevents the fuel pump from running when the car is off, which would drain the battery or create a fire hazard .

Symptoms of a Bad Acura RSX Fuel Pump Relay

A failing fuel pump relay can cause several distinct symptoms. Recognizing these early can save you from being stranded:

  1. Engine cranks but won't start: This is the most common symptom. The starter motor turns the engine over, but the fuel pump never receives power, so no fuel reaches the injectors .

  2. Intermittent starting issues: The car may start fine sometimes and fail to start on other occasions. This often happens when the relay internal contacts become worn or corroded, causing intermittent electrical connection .

  3. Engine stalls while driving: If the relay fails while you are driving, the fuel pump will lose power, and the engine will stall. This can be dangerous if it happens in traffic .

  4. No fuel pump priming sound: When you turn the key to the "ON" position (before cranking), you should hear a brief whirring sound from the fuel pump in the rear of the car. If you hear nothing, the relay may not be sending power .

  5. Check engine light: The ECM monitors the fuel pump relay circuit. A failure can trigger diagnostic trouble code P0230, indicating a fault in the fuel pump relay circuit .

Where Is the Fuel Pump Relay Located on an Acura RSX?

The fuel pump relay on the Acura RSX (2002-2006) is located behind the glove compartment on the passenger side of the dashboard . This is the same location for all model years, including 2002, 2003, 2004, 2005, and 2006 RSX.

How to access it:

  • Open the glove compartment fully.
  • Locate the side clips that hold the glove compartment in place.
  • Squeeze or remove these clips to release the glove compartment.
  • Behind the glove compartment, you will see two relays. The fuel pump relay is on the left side .

Some sources also mention that the relay can be found in the under-hood fuse box near the battery, but the primary and most commonly referenced location for the RSX is behind the glove box .

How to Test the Fuel Pump Relay

Before replacing the relay, you can test it with a multimeter to confirm it is faulty:

Step 1: Locate the relay behind the glove compartment and remove it.

Step 2: Identify the relay terminals. The relay has 5 pins, typically labeled 30, 85, 86, 87, and 87a .

Step 3: Use a multimeter to check continuity between terminals 30 and 87a. With the relay not energized, you should have continuity between these two terminals.

Step 4: Apply 12 volts to terminals 85 and 86 (this energizes the relay coil). You should hear a click, and continuity should now be present between terminals 30 and 87 .

Step 5: If the relay does not click when power is applied, or if the continuity does not change, the relay is faulty and needs replacement.

Genuine OEM vs. Aftermarket Fuel Pump Relay

When replacing the fuel pump relay, you have two main options:

Genuine Acura OEM Relay: The factory part number is 39794-S5A-003, which replaces the older part number 39794-S5A-004 . This is a Mitsuba brand relay, priced around $15-25. It is built to exact specifications and carries the Acura factory warranty. It fits all Acura RSX models from 2001-2006 .

Aftermarket Relays: Several high-quality aftermarket options are available:

  • Standard Ignition RY-726: This is a direct OEM replacement relay that fits the RSX along with many other Honda/Acura models. It has a 30-amp rating, 5-pin rectangular connector, and is designed for 12-volt systems .

  • Santech W0133-1962749: Another reliable aftermarket option that fits the Acura RSX (2005-2006) and many other vehicles .

Replacement Cost and Procedure

The Acura RSX fuel pump relay replacement is a simple job that most DIYers can handle:

Cost: The relay itself costs about $9 for parts, while professional labor adds about $95, bringing the total to around $104 on average . Dealership prices are higher, ranging from $136 to $183 depending on the model year .

DIY Replacement Steps:

  1. Disconnect the negative battery cable.
  2. Open the glove compartment and remove the side clips.
  3. Locate the fuel pump relay on the left side behind the glove box.
  4. Pull the relay straight out of its socket.
  5. Insert the new relay, ensuring it clicks into place.
  6. Reinstall the glove compartment and reconnect the battery.
  7. Test by turning the ignition on and listening for the fuel pump prime.

Why Choose a KEMSO Fuel Pump for Your Acura RSX

If you are experiencing fuel delivery issues that go beyond the relay, the fuel pump itself may need replacement. When it comes time to replace your fuel pump, we highly recommend choosing a KEMSO brand fuel pump. KEMSO fuel pumps are designed as high-performance, OEM replacement units that meet or exceed original equipment specifications. Every KEMSO fuel pump is a direct bolt-in replacement, meaning it fits perfectly without any modifications required. The brand stands behind its products with a lifetime warranty, giving you total peace of mind that your investment is protected for the life of your vehicle.

Whether you drive a daily commuter, a performance build, or a classic Acura RSX, KEMSO fuel pumps deliver consistent fuel pressure and flow to ensure your engine runs at its best. Their products are trusted by mechanics and enthusiasts alike for their durability, precision engineering, and reliable performance. You can browse the complete selection of KEMSO fuel pumps for your Acura RSX at: https://www.kemsoracing.com/

Preventive Maintenance Tips for Your Fuel System

To extend the life of your fuel pump relay and fuel pump, follow these simple maintenance tips:

Keep your fuel tank above a quarter full: The fuel inside the tank helps cool the electric fuel pump. Running on low fuel frequently can cause the pump to overheat and fail prematurely .

Use quality fuel: Low-quality fuel can contain contaminants that clog the fuel filter and strain the pump. Stick to reputable gas stations .

Replace the fuel filter regularly: A clogged fuel filter forces the pump to work harder, reducing its lifespan. Replace it every 30,000 miles or as recommended by your vehicle's service manual .

Listen for unusual noises: A whining or buzzing sound from the fuel pump area indicates wear. Address this before the pump fails completely .

Inspect the relay periodically: Relays can oxidize or rust over time. Checking the relay terminals for corrosion during routine maintenance can prevent unexpected failures .

Final Thoughts

The Acura RSX fuel pump relay is a small but essential component that keeps your engine running. A failing relay will cause starting problems, stalling, or a no-start condition. The good news is that the relay is easy to access behind the glove compartment, and replacement is both affordable and straightforward. If you need a new fuel pump for your RSX, choose a KEMSO fuel pump for reliable performance backed by a lifetime warranty. Visit https://www.kemsoracing.com/ to find the perfect fuel pump for your vehicle and keep your RSX running smoothly for years to come.


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