2005 Toyota Corolla Fuel Pump Relay: Location, Testing, and Replacement Guide

The bottom line: The 2005 Toyota Corolla does not have a dedicated relay labeled "fuel pump." Instead, the fuel system is controlled by the EFI relay, located in the engine compartment fuse box on the driver's side, and the Circuit Opening Relay (C/OPN), which is mounted on top of the fuse block behind the glove box. If your Corolla cranks but won't start, and you've confirmed the fuel pump isn't receiving power, a faulty relay is a common culprit. This guide will walk you through locating both relays, testing them, and replacing them—plus what to check if the relays aren't the problem.

Understanding the Fuel Pump Relay System on a 2005 Corolla

Many Corolla owners search for a single "fuel pump relay" only to find that Toyota uses a two-relay system to control the fuel pump on this generation (E120/E130 chassis, produced 2003–2008). Here is how it works:

  1. EFI Relay (Engine Compartment): This relay, located in the main fuse box under the hood on the driver's side, is the primary power switch for the entire fuel injection system. It sends power to the fuel pump circuit when the ignition is turned to the ON position.
  2. Circuit Opening Relay (C/OPN) (Behind Glove Box): Often called the "C/open" relay, this component sits on top of the interior fuse block behind the glove box. It acts as the second gatekeeper, receiving power from the EFI relay and delivering it directly to the fuel pump.

A failure in either relay will cut power to the fuel pump, producing the same symptom: the engine cranks but never fires because the fuel rail never pressurizes.

Where to Find the EFI Relay (Engine Bay)

The easiest relay to check first is the EFI relay. Here is how to locate it:

  1. Open the hood and look at the fuse box on the driver's side of the engine compartment, near the battery.
  2. Remove the cover. On the inside of the cover, you will see a diagram identifying each fuse and relay.
  3. Look for the EFI relay—it is a small, cube-shaped component with four or five pins. It sits next to the 20-amp EFI fuse.

The EFI fuse itself is a 20-amp yellow fuse labeled "EFI" (for the 1ZZ-FE engine used in most 2005 Corollas). Do not confuse it with the smaller "EFI2" 15-amp fuse, which protects a different portion of the injection system.

Where to Find the Circuit Opening Relay (Behind Glove Box)

The Circuit Opening Relay is trickier to reach. For the 2005 Corolla (ZZE122R and similar Australian/European models), the relay is located on top of the interior fuse block behind the glove box. Here is how to access it:

  1. Open the passenger-side glove box and empty its contents.
  2. Squeeze the sides of the glove box and let it drop down fully, or remove it entirely depending on your trim level.
  3. Look behind the glove box area for the fuse block. You may need to remove a plastic trim panel to see it fully.
  4. The relay is mounted on top of the fuse block. To see it clearly, you may need to unbolt the fuse block and lower it slightly.

Some owners report that the Circuit Opening Relay is bundled within a "Relay Integration" box, which makes visual identification harder. If you cannot locate it, drop the fuse block down as described—the relays are visible from the top once the block is lowered.

How to Test the Relays Before Replacing Anything

Before you buy any parts, test the relays to confirm they are the problem. You will need a digital multimeter (or a 12-volt test light) and a 12-volt power source.

Test 1: Relay Operation (Click Test)

  1. With the relay removed, apply 12 volts to the coil terminals (usually pins 85 and 86) using jumper wires from a battery.
  2. You should hear a distinct click as the internal switch closes.
  3. If there is no click, the relay coil is burned out, and the relay needs replacement.

Test 2: Continuity Check

  1. With the relay energized (clicking), check continuity between the switch terminals (usually pins 30 and 87) using the multimeter's ohms setting.
  2. You should see near-zero resistance (a closed circuit).
  3. When you remove the 12-volt power, the reading should go to infinite resistance (open circuit).
  4. If the switch does not close, the relay contacts are worn or pitted, and the relay is faulty.

Test 3: Swap Test (Quickest Method)

  1. If the horn relay in the same fuse box shares the same part number and pin layout, swap them.
  2. If the horn stops working and the fuel pump starts, your fuel pump relay was bad.

Other Causes of a Dead Fuel Pump (When Relays Are Fine)

If both relays test good and you still have no power at the fuel pump connector, work through this checklist:

  1. Check the EFI and EFI2 fuses: The 20-amp EFI fuse and the 15-amp EFI2 fuse can blow without any visible damage. Pull them and test for continuity with a multimeter.
  2. Verify the fuel pump itself: Disconnect the fuel pump electrical connector (located under the rear seat, on top of the fuel tank) and apply 12 volts directly from a battery. If the pump runs, the problem is upstream.
  3. Inspect the wiring harness: The 2005 Corolla has a known issue where the fuse box can crack after a front-end collision, causing poor pin contact inside the box. Even a hairline crack can interrupt the fuel pump circuit.
  4. Listen for the priming sound: Turn the key to the ON position (do not crank). You should hear a faint whirring from the rear of the car for 2–3 seconds as the pump pressurizes the system. No sound means no power is reaching the pump.

Step-by-Step Relay Replacement

If testing confirms the relay is bad, replacement is straightforward:

  1. Disconnect the battery negative terminal to avoid any short circuits while working.
  2. Remove the faulty relay by pulling it straight up out of its socket. It may require a firm tug.
  3. Compare the new relay with the old one. Confirm the part number matches (for the EFI/Circuit Opening Relay, Toyota part number 90080-87026 is commonly used for 1998–2008 Corollas).
  4. Press the new relay firmly into the socket until it seats completely.
  5. Reconnect the battery and turn the key to ON. Listen for the fuel pump prime sound.
  6. If the car starts, the repair is complete.

Pro tip: Give a stuck relay a gentle tap with the handle of a screwdriver before removing it. Sometimes a stuck relay will free up after a light jolt, saving you the cost of a replacement.

Common Symptoms of a Failing Fuel Pump Relay

Knowing the warning signs can help you catch a failing relay before you are stranded:

  1. Engine cranks but will not start: This is the most common symptom. The starter turns the engine over, but the fuel pump never runs long enough to build pressure.
  2. Intermittent no-start: The car starts fine for days, then suddenly refuses to start. After an hour, it works again. This points to an intermittently failing relay coil.
  3. No fuel pump prime sound: When you turn the key to ON, you do not hear the pump whirring.
  4. Car stalls while driving: If the relay fails while the engine is running, the fuel pump loses power and the engine dies immediately.

Final Thoughts on the 2005 Corolla Fuel Pump Relay

The 2005 Toyota Corolla's fuel pump relay system is reliable, but not indestructible. When it fails, the repair is inexpensive and usually takes less than an hour in your driveway. Always test before replacing, and always replace with a genuine or high-quality relay that matches your car's specifications.

If you have confirmed that both relays are working, the fuses are intact, and the pump runs when powered directly, the problem may lie in the ECU (engine control unit) or the engine's crank position sensor, both of which can prevent the relay from being energized. At that point, professional diagnostic equipment is recommended.

For most owners, however, the fix is exactly what this guide covers: a simple relay swap that gets your Corolla back on the road in no time.

Why Choose a KEMSO Fuel Pump Replacement?

If your fuel pump itself has failed—or you want to replace it proactively while fixing the relay—consider a KEMSO brand fuel pump. KEMSO is known for producing high-performance, OEM-replacement fuel pumps that are built to meet or exceed original factory specifications. Every KEMSO fuel pump comes with a lifetime warranty, giving you peace of mind that your Corolla will stay running for years to come.

You can browse the full KEMSO product lineup, including fuel pumps for Toyota, Honda, BMW, and other popular makes, at https://www.kemsoracing.com/ . Whether you are restoring a classic or upgrading a daily driver, KEMSO has a solution designed for your needs.

For more detailed diagnostic help, consult the 2005 Corolla owner's manual, which includes fuse box diagrams and relay assignments on pages 286–287. If you are working on a non-US market Corolla (such as the ZZE122R), note that relay locations may differ slightly, and the Circuit Opening Relay is almost always behind the glove box.


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