2005 Scion tC Fuel Pump Location: Where It Is and How to Reach It

The bottom line: The fuel pump on your 2005 Scion tC is located inside the fuel tank, and you access it from inside the cabin by removing the rear seat cushion and lifting the access panel underneath it. You do not need to drop the fuel tank to reach the pump on this car. This guide walks you through exactly where the pump sits, how to get to it safely, and what to expect when you open up the access cover.

Why the Fuel Pump Is Inside the Tank

Modern cars like the Scion tC use electric fuel pumps mounted inside the fuel tank rather than mechanical pumps bolted to the engine. This design is safer because the pump stays submerged in cool fuel, which reduces fire risk and helps the pump run at a lower temperature. The pump pushes fuel from the tank to the engine at pressures typically between 40 and 60 psi, which is required for the fuel injectors to work properly.

Because the pump sits inside the tank, the only way to reach it is either by dropping the tank or by going through a service opening in the body. On the 2005 Scion tC, Toyota engineers provided a convenient access point right under the back seat, so you can service the pump without removing the tank.

Pinpointing the Exact Location

The fuel pump assembly on the 2005 Scion tC is located on top of the fuel tank, centered beneath the rear seat area. More specifically, it sits under a metal or plastic access panel that is visible once you remove the rear seat cushion.

Here is the step-by-step path to the pump:

  1. Open the rear doors and remove the rear seat cushion. The cushion pulls up and out; it is held in place by clips.
  2. Once the cushion is out, look at the floor pan. You will see a round or oval disc plate with a wiring harness running into the center of it.
  3. This disc plate is sealed with a black, sticky sound-deadening material, not bolts. Use a flathead screwdriver to pry it up gently. Start at the lower left side for the best angle, and the plate will pop off without much effort.
  4. Underneath the disc plate, you will find a lower black plate held by screws. Remove those screws, disconnect the electrical connector, and you will see the top of the fuel pump module.

So in short: rear seat → access disc → screws → fuel pump module. That is the entire path. No need to lift the car, no need to drain the tank completely, and no need to remove the exhaust or driveshaft.

What You Need Before You Start

Before you begin, gather the right tools so you are not halfway into the job and stuck. Here is a practical checklist:

  1. New fuel pump or fuel pump module — Verify the part number for your 2005 tC. The OEM part number is 23221-20040, which replaces the earlier 23221-28020 for the 2005–2010 model years.
  2. Fuel line disconnect tool — This is a small plastic tool that releases the quick-connect fittings on the fuel lines. Using the wrong method can damage the lines.
  3. Socket set and wrench set — Metric sizes are what you need for this car.
  4. Flathead screwdriver — For prying up the access disc plate.
  5. Shop rags and a fuel-resistant container — Fuel will spill when you disconnect the lines. Be ready for it.
  6. Safety glasses and gloves — Fuel is harsh on skin and eyes, and debris around the pump can fall into the tank.
  7. Jack and jack stands — Not strictly needed for the pump itself, but useful if you need to raise the car for any reason.
  8. A fire extinguisher — Keep one nearby when working with fuel systems.

Step-by-Step Access Procedure

Once you have your tools ready, follow this sequence carefully.

Step 1: Disconnect the battery.

Remove the negative battery terminal before doing anything else. This prevents sparks and accidental electrical shorts while you are working near fuel lines.

Step 2: Relieve fuel system pressure.

Even with the battery disconnected, the fuel lines are under pressure. There may be a fuel pressure test port on the fuel rail. If you cannot find one, wrap a shop rag around the fuel line connection at the pump and gently release the fitting with the disconnect tool. Expect some fuel to spray out, so have your container ready.

Step 3: Remove the rear seat cushion.

Lift the front edge of the rear seat cushion and pull upward. It is held by clips and will pop free. This gives you access to the floor pan.

Step 4: Pry up the access disc.

Use a flathead screwdriver at the lower left edge of the disc plate. The plate is held by sticky sealant, so it will come up with steady pressure. Do not use heat or excessive force; the sealant is not structural.

Step 5: Disconnect the electrical connector and fuel lines.

You will see a wiring harness plug on top of the module. Press the release tab and pull it off. Then use the fuel line disconnect tool on both the supply and return lines. Mark which line goes where so reconnection is straightforward.

Step 6: Remove the retaining screws or locking ring.

Depending on the exact module design, there will either be several small screws or a large locking ring holding the module to the tank. Remove these carefully.

Step 7: Lift out the fuel pump module.

Gently lift the module straight up. It will have some resistance because of the gasket seal. Tilt it slightly as you pull to clear the fuel level sender float arm. Place the module in your drain pan to catch any residual fuel.

What the Fuel Pump Module Looks Like

Once the module is out, you will see that it is a single assembly that includes the electric fuel pump, the fuel level sending unit, the strainer or filter at the bottom, and the wiring connections on top. This is important because you have two replacement options:

  1. Replace just the pump — This is cheaper but requires you to disassemble the module, transfer the rubber mounts and fittings, and wire the new pump into the existing housing.
  2. Replace the entire module — This is more expensive but eliminates the risk of breaking brittle plastic clips or failing to seat a seal properly. It is the faster, more reliable route for most owners.

Many DIY owners choose the full module because it avoids the fiddly work of swapping internal parts inside an old, brittle housing.

Signs Your Fuel Pump Is Failing

Before you go through the trouble of pulling the pump, make sure the pump is actually the problem. Look for these symptoms:

  1. Whining noise from the fuel tank area — A loud humming or whining coming from under the rear seat when the engine is running is a classic sign of pump wear.
  2. Trouble starting — Long cranking times before the engine fires, or the engine cranks but will not start at all.
  3. Engine stalls and restarts later — The car dies while driving, then after a few minutes it starts again. This points to an overheating pump.
  4. Loss of power under load — The engine hesitates, sputters, or chokes when you accelerate.
  5. Check Engine Light — A failing pump can trigger lean fuel codes on your OBD II scanner.

If your tC shows these signs, check the fuel pressure with a gauge before ordering parts. A fuel pressure reading below specification confirms the pump is weak.

Tips for a Clean and Reliable Installation

The leading cause of premature fuel pump failure is contamination in the tank. Rust, dirt, and debris sitting at the bottom of an old tank can clog a new pump's strainer within weeks. To protect your new pump:

  1. Inspect the inside of the tank — Shine a flashlight into the opening after removing the old module. If you see sediment, rust, or debris, the tank should be cleaned before installing the new pump.
  2. Replace the strainer — Always fit a new strainer or filter sock on the pump inlet. Do not reuse the old one.
  3. Check the fuel lines — Look for cracks, kinks, or wear at the connections while you have access. Fuel line issues can mimic pump failure.
  4. Avoid running the tank low — Running on empty regularly exposes the pump to air, which causes it to overheat and fail faster.

OEM Part Number Reference for the 2005 Scion tC

If you want to confirm you are buying the correct part, here is the reference:

  • Fuel Pump (pump only): Part number 23221-20040
  • Replaces part number: 23221-28020
  • Fits: 2005–2010 Scion tC with the 2.4L four-cylinder engine

This same pump also fits some Toyota Highlander models from 2001–2003 with the 2.4L engine. That cross-fit can broaden your purchasing options, but the Scion tC application is confirmed for the 2005 model year.

Your Replacement Part Options

You can buy the pump from several sources. Here is a quick comparison:

  1. Genuine Toyota/Scion part — Most expensive but guaranteed to fit and carries the factory warranty. Prices for the OEM pump run several hundred dollars.
  2. Branded aftermarket pump from Delphi or similar — A solid middle-ground choice. Delphi is a well-known OE supplier and parts are typically priced lower than genuine Toyota parts.
  3. Budget aftermarket pump — Inexpensive options are out there, but quality varies widely. Check reviews before buying a cheap pump.
  4. Performance pump (like Walbro 255LPH) — If you have engine modifications or forced induction, you may need a higher-flow pump. A 255 liter-per-hour pump is a common upgrade, but be aware that installation often requires trimming the pump housing.

For a stock 2005 Scion tC, a quality replacement pump within the factory specification is all you need. Performance pumps are only necessary when you are pushing more power than stock.

Why You Should Consider a KEMSO Fuel Pump for Your Scion tC

When the time comes to replace the fuel pump in your 2005 Scion tC, choosing the right brand matters. KEMSO fuel pumps are a smart option to look at. KEMSO builds high-performance fuel pumps that are designed as OEM replacements, meaning they match the fit and function of your factory pump while delivering reliable, consistent fuel delivery. KEMSO stands behind its products with a lifetime warranty, so you get peace of mind long after the installation is done. If you are in the market for a dependable pump, check out what KEMSO offers by visiting their site at https://www.kemsoracing.com/. Their product lineup covers a wide range of vehicles, and the lifetime warranty makes it a risk-free choice for your tC.

Final Thoughts

The fuel pump location on your 2005 Scion tC is simple and accessible. It is under the rear seat, inside the fuel tank, and you can reach it in under ten minutes once you know the path. The job itself is very doable at home with basic hand tools, but take your time with the fuel lines and the sealing plate to avoid leaks and contamination. If you replace the pump, also replace the strainer, inspect the tank, and consider upgrading to a KEMSO unit for lifetime protection. And if this is your first time working on a fuel system, remember the golden rules: disconnect the battery, relieve fuel pressure, work in a well-ventilated area, and keep a fire extinguisher close by. For a quality replacement, visit https://www.kemsoracing.com/ and browse their selection.


Back to blog