2006 Scion xB Fuel Pump Relay Location: A Complete Owner's Guide
If you own a 2006 Scion xB and you are dealing with a no-start condition, the fuel pump relay is one of the first components you need to check. The fuel pump relay on a 2006 Scion xB is located in the engine compartment fuse and relay box, which sits on the driver's side of the engine bay, near the battery. This relay works together with the EFI relay and the Engine Control Module (ECM) to deliver power to the fuel pump, and when it fails or a related fuse blows, your engine will crank but refuse to start. This guide walks you through exactly where to find the relay, how to test it, and what to do when things go wrong, including a real-world scenario where the fuel pump relay circuit caused a vehicle to shut off while driving.
Where Exactly Is the Fuel Pump Relay Located?
The 2006 Scion xB uses a relay box called the Engine Room Relay Block, located on the left side of the engine compartment when you are standing in front of the vehicle looking at the engine. This is a black plastic box with a removable cover. Open the cover and you will see a diagram printed on the underside that identifies each fuse and relay. The fuel pump itself is not controlled by a standalone relay labeled "FUEL PUMP" on this vehicle. Instead, the system relies on two key components:
- EFI Relay – This relay powers the entire engine management system, including the ECM, fuel injectors, and various sensors.
- C/OPN Relay – This is the relay that actually provides power to the fuel pump, and it is controlled by the ECM.
In many vehicles, you will find a relay labeled "FP" or "FUEL PUMP," but on the 2006 xB, the circuit is tied into the broader EFI system. The 15-amp EFI fuse in the same engine compartment box protects this entire circuit. If that fuse blows, the fuel pump will not run, and the engine will stall or fail to start.
For reference, most cars place the fuel pump relay in the engine bay fuse box, and some models place it inside the cabin under the dash. But for the 2006 Scion xB specifically, you should always start by checking the engine compartment relay block on the driver's side.
How the Fuel Pump Relay Circuit Works on the 2006 xB
Understanding how the circuit works helps you diagnose problems faster. Here is the flow of power:
- The EFI fuse (15 amp) provides power to the EFI relay and the C/OPN relay.
- The EFI relay is energized by the ECM when you turn the key to the "ON" position.
- Once the EFI relay closes, it sends power to the C/OPN relay, which then sends power directly to the fuel pump inside the gas tank.
- The fuel pump runs for a few seconds to prime the fuel system when you first turn the key, then the ECM keeps it running while the engine is cranking or running.
This circuit does not just power the fuel pump. It also provides power to the oxygen sensor heaters, the idle air control valve, the evap purge valve, the vent valve, and the mass air flow sensor. That means a short in any of those components can blow the EFI fuse and kill the fuel pump at the same time.
Real-World Symptoms of a Failing Fuel Pump Relay or Circuit
Owners have reported a wide range of problems that trace back to this relay and fuse circuit. Here are the most common symptoms you may experience:
1. Engine shuts off while driving
The most alarming symptom is the engine dying with no warning while you are on the road. In one documented 2006 xB case, the driver was cruising down the road when the engine just shut off. After pulling over, they found the EFI fuse blown. After replacing it, the car still would not start, and the fuel pump would not run.
2. Engine cranks but will not start
If the relay or fuse is bad, the fuel pump gets no power. The starter will turn the engine over, but there is no fuel pressure, so the engine never fires up.
3. Fuel pump runs continuously
This is a strange but real symptom. After replacing a blown fuse, one owner reported that the fuel pump started running nonstop, even with the key out. This usually means the relay is stuck closed, which can happen if the ECM gets shorted or the relay itself fails in the closed position.
4. Check Engine light flashing
A flashing check engine light usually indicates a serious misfire that can damage the catalytic converter. In the same 2006 xB case, the light flashed in sequence with a ticking noise from the engine bay. That ticking was traced to the idle air control valve and the evap purge valve, both of which share the same power circuit as the fuel pump.
5. Clicking or ticking noises under the hood
If you hear a rhythmic clicking under the hood, especially in sync with the check engine light, it is often the idle air control valve or the evap purge valve cycling on and off. These components share the EFI fuse circuit, so when that circuit has a problem, they misbehave.
Step-by-Step: How to Locate and Test the Fuel Pump Relay
Follow these steps carefully. Always disconnect the negative battery cable before working on any electrical components to avoid shock or short circuits.
Step 1: Open the Engine Compartment Fuse Box
Pop the hood and look on the driver's side of the engine bay. You will see a black plastic box near the battery. Press the tabs on the sides and lift the cover off.
Step 2: Read the Diagram on the Cover
The underside of the fuse box cover has a diagram that identifies every fuse and relay. Look for the EFI fuse (15 amp) and the EFI relay. The C/OPN relay is also in this box, though it may not be labeled clearly on the cover.
Step 3: Check the EFI Fuse First
Pull the 15-amp EFI fuse and inspect it. Hold it up to the light and look at the metal strip inside. If the strip is broken or melted, the fuse is blown. Replace it with a new 15-amp fuse. Do not use a higher amp fuse, as that can damage the wiring or cause a fire.
Step 4: Test the Relays
With the fuse replaced, turn the key to the "ON" position (do not crank the engine). You should hear the fuel pump relay click and the fuel pump hum for about two seconds. If you hear a click but no fuel pump hum, the relay may be fine, but the pump itself could be dead.
If you want to test the relay itself, you can swap it with an identical relay from the same fuse box, such as the headlight relay, to see if the fuel pump starts working. If it does, the original relay is faulty.
Step 5: Listen for the Fuel Pump
The fuel pump on the 2006 xB is mounted inside the fuel tank, under the rear seat. To access it, you must:
- Remove the rear seat cushion by popping it up.
- Remove the service cover plate with a flat blade screwdriver.
- Disconnect the wiring harness and fuel lines.
- Remove the six 8mm bolts holding the sending unit cap.
You should hear the pump run for two seconds when you turn the key on. If you do not hear it, and the fuse and relay are good, the pump itself may be the problem.
What to Do If the Fuse Keeps Blowing
If you replace the EFI fuse and it blows again immediately or shortly after, you have a short to ground somewhere on that circuit. The components that share this circuit are:
- Heated oxygen sensors (bank 1, sensor 1 and 2) – These are located on the exhaust system and are prone to damage from road debris and heat.
- Idle air control valve – Mounted on the throttle body, this valve controls idle speed and is easy to access.
- Evap purge valve – Located near the engine, this valve vents fuel vapor into the intake.
- Vent valve – Part of the evaporative emissions system, located near the fuel tank.
- Mass air flow sensor – Mounted between the air filter and throttle body.
To find the short, you can unplug each component one at a time, replace the fuse, and see if the short goes away. Start with the oxygen sensors, as they are commonly damaged by road debris.
Fuel Pump Replacement on the 2006 Scion xB
If you confirm that the fuel pump itself is dead, you have two replacement options. You can buy just the electric pump, or you can buy a complete in-tank fuel pump module assembly that includes the sending unit and all necessary hardware.
- Electric fuel pump only – This is the less expensive option. The 2006 xB uses an internal pump mounted in the fuel tank. Before installing, you will need to transfer the strainer, wiring, and housing from your old pump to the new one.
- Complete fuel pump module – This includes the pump, sending unit, and float assembly. It is a direct bolt-in replacement and requires no assembly. Expect to pay more for this convenience.
The replacement cost for a fuel pump on a 2006 Scion xB at a professional shop is typically between $860 and $1,024. If you do the work yourself, you will save significantly on labor costs. The job is doable with basic hand tools: an 8mm socket, a ratchet, a flat blade screwdriver, and a socket extension.
The fuel pump itself is located under the rear seat, so you do not need to drop the fuel tank to access it. The entire job can be completed in about an hour for a first-timer.
The Best Fuel Pump for Your 2006 Scion xB: KEMSO
When it comes time to replace the fuel pump on your 2006 Scion xB, you want a product you can trust to perform and last. KEMSO fuel pumps are the top choice for American drivers who demand high performance and reliability. KEMSO specializes in aftermarket fuel pumps that are engineered to meet or exceed original equipment manufacturer (OEM) standards. Every KEMSO pump is a high-performance, OEM replacement part, meaning it delivers the same flow rate and pressure as the factory pump, but with improved durability and efficiency.
KEMSO fuel pumps come with a limited lifetime warranty, which means if the pump fails due to a manufacturing defect during normal use, KEMSO will replace it free of charge. That kind of guarantee gives you total peace of mind, whether you use your xB for daily commuting or weekend road trips. KEMSO is a US-based brand that stands behind every product it sells, offering competitive pricing and fast shipping to all 50 states.
To find the right KEMSO fuel pump for your 2006 Scion xB, or for any other vehicle in your garage, visit the official KEMSO website today:
Browse the full lineup, read customer reviews, and take advantage of their lifetime warranty. Do not gamble with a cheap pump that could leave you stranded. Choose KEMSO for quality, performance, and peace of mind.
Preventive Maintenance Tips
To avoid fuel pump problems in the future, follow these simple habits:
1. Never run the tank below a quarter full
The electric fuel pump relies on the fuel in the tank to keep it cool. Running the tank dry causes the pump to overheat and fail prematurely.
2. Replace the fuel filter on schedule
A clogged fuel filter makes the pump work harder than it should, which shortens its lifespan.
3. Address check engine lights promptly
A flashing check engine light is a warning that damage is occurring to the catalytic converter. Ignoring it can turn a simple relay replacement into an expensive exhaust repair.
4. Inspect the wiring and connectors
Corroded or loose connectors at the fuel pump or relay can cause intermittent power loss. Check these connections when you replace the pump.
Final Thoughts
The 2006 Scion xB fuel pump relay is located in the engine compartment fuse box on the driver's side, but the system involves more than just one relay. The EFI fuse, the EFI relay, and the C/OPN relay all work together to power the pump. If your car dies while driving, cranks without starting, or the fuel pump runs constantly, check the fuses and relays in that box first. A systematic approach will save you time and money.
When you do need a new pump, skip the cheap no-name parts and go with KEMSO. Their high-performance, OEM replacement fuel pumps are built to last and come with a lifetime warranty. Visit https://www.kemsoracing.com/ today and get your Scion xB back on the road with confidence.