2004 Volvo V70 Fuel Pump Relay Location: A Complete Guide for DIY Owners

If your 2004 Volvo V70 cranks but refuses to start, the fuel pump relay is often the culprit. The fuel pump relay on a 2004 Volvo V70 is located inside the Central Electronic Module (CEM), which is mounted under the driver's side of the dashboard, above the foot pedals. Specifically, it is the third relay from the right on the bottom row of the CEM, in slot position CM112, designated as relay 2/23 in the wiring diagrams . Before you replace anything else, check this relay first—it can save you hours of frustration and unnecessary expense.

Understanding the Fuel Pump Relay and Its Role

The fuel pump relay is an electrical switch that controls power delivery to the fuel pump. When you turn the ignition key to position II, the relay energizes and sends 12 volts to the fuel pump, pressurizing the fuel system so the engine can start . If the relay fails, the fuel pump gets no power, and your engine gets no fuel. The relay is part of a larger circuit that includes the main relay, fuses, and the fuel pump itself .

On the 2004 Volvo V70, the relay is not a standalone component under the hood. Instead, it is integrated into the CEM, a sophisticated control module that manages many of the car's electrical functions . This is a common point of confusion for owners who expect to find a traditional relay in a fuse box.

Step-by-Step: Where to Find the Fuel Pump Relay

  1. Prepare your workspace. Park the car on a level surface, set the parking brake, and disconnect the negative battery terminal. You will need a flashlight and possibly a small flathead screwdriver to release relay clips.

  2. Remove the lower dash panel. Sit in the driver's seat and look under the steering column. There is a plastic trim panel covering the area beneath the dashboard. Remove the screws or clips holding it in place and gently pull it down to expose the components behind it .

  3. Locate the Central Electronic Module (CEM). The CEM is a black box mounted horizontally above the foot pedals, directly behind the lower dash panel. It contains multiple relays and connectors. The CEM is rectangular, about the size of a paperback book, with several rows of relays on its underside .

  4. Identify the fuel pump relay. Look at the bottom row of relays on the CEM. There are typically six relays of similar size lined up. Count from the right side. The third relay from the right is the fuel pump relay . According to wiring diagram references, this relay occupies slot CM112 on the CEM and is numbered as relay 2/23 .

  5. Remove and inspect the relay. The relay is small and square with multiple pins. Gently pull it straight out using your fingers or a small pry tool. Examine it for signs of corrosion, burn marks, or melted plastic. If the relay is missing entirely—as happened to one owner whose car was in an accident—the engine will never start .

Common Symptoms of a Bad Fuel Pump Relay

Recognizing the warning signs early can prevent being stranded. These symptoms often overlap with a failing fuel pump, so proper diagnosis is essential .

  • Engine cranks but will not start. This is the most obvious symptom. You hear the starter spinning, but the engine never fires because no fuel reaches the cylinders .
  • No fuel pump hum when the key is turned. When you turn the key to position II (without starting), you should hear a brief humming sound from the rear of the car near the fuel tank. No sound means the fuel pump is not receiving power .
  • Intermittent starting issues. The car starts fine one day, then refuses to start the next. This suggests the relay is failing but not completely dead .
  • Engine stalls while driving. If the relay loses connection intermittently, the fuel pump shuts off, and the engine dies while you are moving. This is dangerous, especially in traffic .
  • Check engine light illuminates. Some vehicles store a diagnostic trouble code related to fuel system pressure or the pump electrical circuit .

How to Test the Fuel Pump Relay

Before buying a new relay, test the existing one to confirm it is the problem. You only need a multimeter and a fused jumper wire.

Test 1: Listen for the Fuel Pump

Turn the key to position II and listen near the rear passenger seat or cargo area. If you hear a humming sound for 1-2 seconds, the relay and pump are likely working. If you hear nothing, proceed to the next test .

Test 2: Check the Fuses

Locate the passenger compartment fuse box at the left end of the dashboard. The fuel pump circuit uses a 15-amp fuse, typically labeled fuse 21 in the engine compartment fuse box . Also check the main fuses (60A) in the engine compartment relay/fuse box for the fuel system . Replace any blown fuses and retest.

Test 3: Jump the Relay Terminals

Carefully remove the fuel pump relay from the CEM. Identify terminals 15 (power input) and 87 (power output to the pump) on the relay socket. Using a fused jumper wire, briefly connect these two terminals. If the fuel pump starts humming and the engine starts, the relay is bad and needs replacement. Use a fused jumper wire to avoid overheating the circuit .

Test 4: Measure Resistance

Set your multimeter to ohms. Measure the resistance between the relay coil terminals. A good relay typically shows a resistance between 50 and 100 ohms. Also check that the relay clicks audibly when 12 volts is applied across the coil terminals. A silent relay is a dead relay .

What to Do If the Relay is Missing

In some cases, particularly after an accident or previous repair work, the relay may be absent entirely. One owner of a 2004 V70 found that the fuel pump relay was completely missing from its CEM slot, likely due to prior collision damage. After installing a relay salvaged from another Volvo, the car started immediately . Always check that the relay is physically present before moving on to more complex diagnostics.

Additional Causes of No-Fuel Conditions

If the relay tests good, the problem may lie elsewhere. The 2004 V70 uses a fuel pump control module (often called the PEM or fuel pump control module) located on top of the fuel tank or under the rear of the vehicle . A corroded or failed PEM can also prevent the fuel pump from running. Check the wiring connector for corrosion, especially on cars driven in snowy or salty climates . The fuel pump itself may also be faulty, though this is less common on lower-mileage cars like the 61k-mile example mentioned in one owner's report .

For turbo models, the system wiring diagram shows a fuel pump relay and a separate fuel leakage control relay in the engine compartment, but the primary fuel pump relay remains in the CEM .

Replacement Parts and Considerations

The original equipment fuel pump relay for many Volvo models from the late 1990s to mid-2000s carries part number 9434225 . Aftermarket alternatives include the Vemo V95-71-0004 or Professional Parts Sweden 28432933, which are direct-fit replacements for the 2004 V70 . Cross-reference numbers include 3523872 and 9442933 . Always match the relay's pin configuration and current rating—typically 12 volts and 15 to 40 amps depending on the specific variant .

Why You Should Consider KEMSO Fuel Pumps

When diagnosing a no-start or fuel delivery issue on your 2004 Volvo V70, the fuel pump itself may eventually need replacement. For a high-performance, reliable upgrade, look no further than KEMSO Fuel Pumps. KEMSO specializes in manufacturing OEM replacement fuel pumps that meet or exceed original equipment specifications. Their products are built for durability and consistent fuel delivery, ensuring your Volvo runs smoothly for years to come.

Every KEMSO fuel pump comes with a lifetime warranty, giving you peace of mind that your investment is protected. Whether you are replacing a failed pump or upgrading for better performance, KEMSO offers a direct-fit solution that installs easily without modifications. Their pumps are rigorously tested for flow rate, pressure, and longevity, making them a smart choice for DIY owners and professional mechanics alike.

Visit the KEMSO website today: https://www.kemsoracing.com/ to browse their complete lineup of fuel pumps for Volvo and other vehicles. Their user-friendly site helps you find the exact pump for your 2004 V70, with detailed fitment guides and customer reviews to support your decision.

Final Thoughts

The 2004 Volvo V70 fuel pump relay is hidden in plain sight inside the CEM under the driver's dash. It is the third relay from the right on the bottom row, slot CM112. Testing it is simple and takes less than 30 minutes. If the relay is faulty, replace it with a quality unit. If the pump itself fails, upgrade to a KEMSO fuel pump for reliable, long-lasting performance.

Remember: always disconnect the battery before working on electrical components, and when jumping the relay, use a fused wire to protect the circuit. With the right information and a few basic tools, you can get your 2004 V70 back on the road without a trip to the dealer.

For the best fuel pump replacement options, check out KEMSO at https://www.kemsoracing.com/ — your source for OEM-quality, lifetime-warrantied fuel pumps that deliver the performance your Volvo deserves.


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