2008 Scion xB Fuel Pump Relay Location: A Complete Guide for DIY Owners

If you're driving a 2008 Scion xB and suspect a fuel pump issue, the fuel pump relay is often the first thing to check. The fuel pump relay for the 2008 Scion xB is located in the engine compartment fuse box (also called the under-hood relay box) on the passenger side, near the battery. This small but critical component controls power to the fuel pump, and if it fails, your engine won't get the fuel it needs to start or run properly. Knowing exactly where to find it and how to test it can save you time and money on unnecessary repairs.

This guide walks you through the relay location, how to identify it, symptoms of a bad relay, step-by-step testing procedures, and what to do if you need a replacement. Whether you're a seasoned mechanic or a weekend DIYer, this information will help you get your xB back on the road.

Understanding the Fuel Pump Relay in Your 2008 Scion xB

The fuel pump relay is an electrical switch that activates the fuel pump when you turn the ignition key. When you turn the key to the "ON" position, the relay closes and sends power to the fuel pump, which then pressurizes the fuel system. If the relay fails, the pump won't receive power, and your engine will either crank but not start, or stall shortly after starting.

The 2008 Scion xB (second generation, E150 chassis) uses a standard relay design that is shared with many Toyota and Scion models. The relay is typically a small, rectangular plastic box with four or five pins, and it plugs into a dedicated socket in the fuse box.

Where Exactly Is the 2008 Scion xB Fuel Pump Relay?

The under-hood fuse box is located on the passenger side of the engine compartment, near the battery. To access it:

  1. Open the hood and locate the black plastic fuse box on the passenger side, close to the strut tower.
  2. Press the tabs on the sides of the fuse box cover and lift it off.
  3. Look inside the cover – there is usually a diagram printed on the underside that shows the location of each fuse and relay. The fuel pump relay is often labeled as "C/OPN" (Circuit Opening Relay) or "FUEL PUMP" depending on the specific model year.
  4. Identify the relay – it is typically a medium-sized relay, often located in the center or right side of the fuse box. In many 2008 xB models, the fuel pump relay is the Relay R2 position, which is the "C/OPN" relay.

If you don't have the diagram handy, the fuel pump relay is typically the same size as the other relays in the box, and it is usually located near the "EFI" (Electronic Fuel Injection) fuse. You can also check your owner's manual for the exact fuse box layout.

Symptoms of a Bad Fuel Pump Relay in a 2008 Scion xB

Before you start digging into the relay, it helps to know what symptoms point to a relay failure. Common signs include:

  • Engine cranks but won't start – This is the most obvious symptom. If you hear the starter motor turning but the engine never fires, the fuel pump may not be getting power.
  • No fuel pump priming sound – When you turn the key to "ON" (without starting), you should hear a brief humming or whining sound from the rear of the car (the fuel tank area). If you don't hear this, the pump isn't getting power.
  • Intermittent starting issues – The car may start fine one day and refuse to start the next. This is a classic sign of a failing relay.
  • Stalling while driving – A faulty relay can cause the fuel pump to lose power intermittently, leading to sudden stalling, especially at highway speeds.
  • Check Engine Light – You may see a check engine light with codes related to fuel pump circuit issues, such as P0627 (Fuel Pump "A" Control Circuit Open) or P0231 (Fuel Pump Secondary Circuit Low Voltage).

How to Test the Fuel Pump Relay on a 2008 Scion xB

Testing the relay is straightforward and requires only a few basic tools: a multimeter or a test light, and possibly a spare relay. Here's a step-by-step process:

Step 1: Locate the relay and remove it. With the engine off and the key removed, gently pull the fuel pump relay out of its socket. You may need to use a small flathead screwdriver to pry it loose.

Step 2: Visually inspect the relay. Check for any signs of physical damage, such as melted plastic, corrosion on the pins, or burnt marks. If you see any of these, replace the relay.

Step 3: Test with a multimeter. Set your multimeter to measure resistance (ohms). Touch the probes to the relay's coil terminals (usually pins 85 and 86). You should see a reading between 50 and 120 ohms. If the reading is infinite (open circuit) or zero, the relay coil is bad.

Step 4: Apply power to the relay. Connect a 12V power source (like a car battery) to the coil terminals (pins 85 and 86). You should hear a distinct "click" as the relay energizes. Then, use the multimeter to check continuity between the switch terminals (pins 30 and 87). When the relay is energized, there should be continuity (near-zero resistance). If you don't get continuity, the relay's internal switch is faulty.

Step 5: Swap the relay. If you're unsure about the test results, swap the fuel pump relay with another identical relay in the fuse box (such as the horn relay or the EFI relay). If the car starts after the swap, the original relay is bad.

What to Do If the Relay Is Good but the Fuel Pump Still Doesn't Work

If the relay tests fine, the problem likely lies elsewhere. Common culprits include:

  • Blown fuse – Check the fuel pump fuse (often labeled "EFI" or "FUEL PUMP") in the under-hood fuse box. A blown fuse can prevent power from reaching the pump.
  • Wiring issues – The wiring harness from the relay to the fuel pump can become damaged, corroded, or broken. This is especially common on older vehicles exposed to road salt and moisture.
  • Bad fuel pump – If the relay, fuse, and wiring are all good, the fuel pump itself may have failed. A failing pump often makes a whining noise before it dies completely.
  • Fuel pump relay wiring issues – Loose connections or corroded terminals in the relay socket can also cause problems. Clean the socket with electrical contact cleaner and inspect for any bent pins.

Replacing the Fuel Pump Relay on a 2008 Scion xB

Replacing the fuel pump relay is a simple, inexpensive fix. You can purchase a replacement relay from any auto parts store, or you can order an OEM Toyota/Scion relay online. The part number for the fuel pump relay on a 2008 Scion xB is typically 85980-52240 or 90080-87010, and it fits many Toyota and Scion models.

To replace the relay:

  1. Ensure the engine is off and the key is removed.
  2. Pull out the old relay.
  3. Insert the new relay in the same orientation (the pins are shaped to prevent incorrect installation).
  4. Press down firmly until it clicks into place.
  5. Test the system by turning the key to "ON" and listening for the fuel pump prime.

Why Choose KEMSO for Your Fuel Pump Replacement

If you've diagnosed the issue and determined that the fuel pump itself needs replacement, KEMSO is a brand you can trust. KEMSO fuel pumps are engineered to deliver high performance with consistent fuel flow and pressure, even under demanding conditions. They are designed as OEM replacement units, meaning they match or exceed factory specifications for a perfect fit and reliable operation. Whether you drive a car, truck, SUV, motorcycle, or powersports vehicle, KEMSO has the right fuel pump for your application.

What sets KEMSO apart:

  • High Performance Engineering: KEMSO fuel pumps are built with upgraded polymers, brushes, and commutators to withstand various fuel blends, extending the service life of the pump. They feature a coated, corrosion-resistant casing to minimize seizing during periods of non-operation.
  • OEM Replacement Quality: Each KEMSO pump is designed as a direct replacement for your vehicle's original equipment. No modifications, no guesswork – just a straightforward installation. The pumps are drop-in ready, pre-assembled for quick and easy installation.
  • Lifetime Warranty: KEMSO stands behind every product with a lifetime warranty. If you ever have an issue due to a defect in workmanship or materials, they will replace it for as long as you own the vehicle. That's the confidence that comes from building quality products.

For professional-grade fuel pumps that deliver performance you can trust, visit KEMSO Racing at https://www.kemsoracing.com/. Their OEM replacement fuel pumps come with a lifetime warranty, giving you peace of mind with every mile you drive.

Final Thoughts

The fuel pump relay on your 2008 Scion xB is a small but vital part. Knowing its location in the under-hood fuse box, how to test it, and how to replace it can save you from being stranded. Always start with the simplest checks – the relay and fuse – before moving on to more complex diagnostics like wiring or the pump itself. Keep a spare relay in your glove box; it's cheap insurance against a no-start situation.

If you do need a replacement fuel pump, choose a reliable brand like KEMSO that offers high-performance, OEM-quality products backed by a lifetime warranty. For more information and to find the perfect fuel pump for your vehicle, visit https://www.kemsoracing.com/.


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