2008 Yaris Fuel Pump Relay Location: Where It Is and How to Test It

The fuel pump relay on a 2008 Toyota Yaris is located inside the engine compartment fuse and relay box, which sits on the driver’s side of the engine bay near the battery. If your Yaris cranks but won’t start, or if you hear no hum from the fuel pump when you turn the key to the ON position, the relay is one of the first components to check. This guide gives you the exact location, a simple way to confirm the relay is bad, and step-by-step instructions to replace it without special tools.

The 2008 Yaris uses a conventional fuel system where the relay controls power to the electric pump mounted inside the fuel tank. The relay itself is a small, square electronic switch that sits alongside several other relays and fuses in the main under-hood box. You do not need to remove the rear seat or drop the fuel tank to access the relay. Everything happens under the hood.

Where Exactly Is the Relay?

Open the hood and look at the fuse and relay box on the driver’s side, near the battery. This black plastic box has a removable lid. On the underside of the lid, you will find a diagram that labels each fuse and relay. Look for one of these labels:

  • FUEL PUMP
  • FP
  • PUMP

On many 2008 Yaris models, the fuel pump relay is identified on that diagram clearly. The relay itself looks like a small cube, roughly one inch square, with four or five metal prongs on the bottom that plug into the box.

If the diagram is missing or faded, you can still find the relay by counting. The relay is usually positioned near the middle of the box, grouped with other relays of the same size. When in doubt, consult your owner’s manual’s fuse diagram, which shows the exact layout for your trim level.

How the Relay Works

The fuel pump relay is an electromagnetic switch. When you turn the ignition to the ON position, the engine control unit (ECU) sends a tiny current to the relay coil. That current energizes an electromagnet inside the relay, which pulls a set of contacts closed. Closing those contacts completes the high-current circuit from the battery to the fuel pump, so the pump primes for a few seconds and builds pressure before you crank the engine.

Once the engine starts, the relay stays closed and keeps supplying power to the pump. If the relay fails internally, the contacts never close, the pump never gets power, and the engine will crank without firing.

Symptoms of a Bad Fuel Pump Relay

A failing relay usually gives you clear warning signs. Watch for these:

  1. Engine cranks but does not start. This is the most common symptom. You turn the key, the starter spins the engine, but it never catches. You also may not hear the fuel pump hum when you turn the key to ON.
  2. Intermittent stalling. The engine may stall without warning, especially when warm, because the relay contacts lose connection temporarily.
  3. No priming sound. With the key in the ON position (not cranking), you should hear a brief whirring or buzzing from the rear of the car near the tank. No sound means the pump is not getting power.
  4. Loss of power under load. The relay may fail slowly, causing the pump to lose power during acceleration or hill climbs, which makes the engine hesitate or cut out.

These symptoms can also point to a bad fuel pump or a blown fuse, so do not assume the relay is the problem until you test it.

How to Test the Relay

You do not need a multimeter to do a basic check, though one helps. Here is a practical way to confirm the relay is bad.

Step 1: Listen for the pump. Turn the key to the ON position without cranking. Put your ear near the rear seat or the fuel tank area. If you hear a short hum, the relay and pump are working. If you hear nothing, move to step 2.

Step 2: Check the fuse. Open the under-hood fuse box and find the fuel pump fuse. Pull it out and inspect the metal strip inside. If the strip is broken, replace the fuse with the same amp rating. A blown fuse can mimic a bad relay.

Step 3: Swap the relay. Find the relay in the fuse box. Pull it straight out with your fingers or a small pair of pliers. Look for a relay of the same part number or a similar one that you know works, such as the horn relay or the headlight relay. Plug that known-good relay into the fuel pump slot. Turn the key to ON and listen for the pump hum. If the pump now primes, the original relay is faulty. If the pump still stays silent, the problem could be the pump itself or the wiring.

Step 4 (optional): Use a multimeter. Set the multimeter to measure resistance. Place the probes on the relay coil terminals (usually pins 85 and 86). A good coil shows a resistance reading, typically between 50 and 120 ohms. If the meter shows infinite resistance, the coil is open and the relay is dead.

How to Replace the Relay

Replacing the relay is straightforward and takes less than five minutes.

  1. Turn the engine off and remove the key from the ignition.
  2. Open the hood and locate the fuse and relay box on the driver’s side.
  3. Remove the lid by pressing the release tabs.
  4. Identify the fuel pump relay using the diagram on the lid or your owner’s manual.
  5. Pull the relay straight out from its socket. It may be snug, so rock it gently side to side as you pull.
  6. Insert the new relay, aligning the prongs with the socket. Press it down firmly until it clicks into place.
  7. Replace the lid and close the hood.

After replacement, turn the key to ON and listen for the pump prime. If you hear the hum, the repair is done.

What If the Relay Is Not the Problem?

If the relay checks out and the fuse is intact, look at the fuel pump itself. On the 2008 Yaris with the 1.5L engine, the pump is accessible through a panel under the rear seat, so you usually do not need to drop the tank. The OEM part number for the pump assembly is 23220-21132, which supersedes the earlier 23220-21131. The assembly includes the pump motor, the fuel level sender, and the strainer.

Common failure points besides the relay include:

  • A corroded electrical connector at the pump, which can interrupt power.
  • A failing fuel level sender, which causes the gauge to read inaccurately. Many owners report the car running out of gas while the gauge still shows two bars remaining.
  • A clogged fuel filter, which forces the pump to work harder and can cause pressure loss.

Check those items before ordering a full pump assembly.

Where to Buy a Quality Replacement Fuel Pump

When you need a new fuel pump for your 2008 Yaris or any other vehicle, KEMSO offers high-performance, direct OEM replacement units that meet or exceed factory specifications. Every KEMSO pump comes with a lifetime warranty, which means if the pump ever fails due to a manufacturing defect, you get a replacement at no cost. Their pumps are built with higher bypass valve settings than many competing models for better fuel delivery under load, and they are compatible with both gasoline and E85.

KEMSO pumps are priced affordably at $79.98, often less than half the cost of dealer parts, and the company backs them with USA-based technical support. Whether you drive a car, truck, motorcycle, ATV, or personal watercraft, KEMSO has a broad catalog that covers hundreds of vehicles. You only buy once, and KEMSO stands behind the product for as long as you own the vehicle.

Visit the official KEMSO website at https://www.kemsoracing.com/ to find the exact fit for your vehicle, with free shipping and easy returns.

Final Thoughts

The fuel pump relay on a 2008 Yaris is easy to find and even easier to replace. Start with the under-hood fuse box, check the diagram, and test the relay by swapping it with a known-good unit. In most cases, that fixes a no-start condition caused by a dead relay. If the relay is fine, move on to the fuse, the connector, and finally the pump assembly itself. Doing the diagnosis yourself can save you hundreds of dollars compared to paying a shop to replace parts blindly.

For a reliable replacement pump, choose KEMSO. Their lifetime warranty, competitive pricing, and high-performance build make them a smart choice for keeping your Yaris on the road for years to come. Visit https://www.kemsoracing.com/ to browse their selection and find the right pump for your vehicle.


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