2006 Chevy Cobalt Fuel Pump Relay: Location, Testing, and Replacement Guide

The 2006 Chevy Cobalt fuel pump relay is located in the underhood fuse block, also known as the engine compartment fuse box, and it is labeled as relay R2. If your Cobalt cranks but won't start, or you hear no fuel pump prime when you turn the key, this relay is one of the first components to check. A faulty relay can interrupt power to the fuel pump, preventing fuel from reaching the engine. This guide will show you exactly where to find it, how to test it, and how to swap in a new one—along with a look at the OE part number and a smart upgrade path for your fuel system.

What Does the Fuel Pump Relay Do?

The fuel pump relay is an electrical switch that controls power to the fuel pump. When you turn the ignition key to the ON position, the Powertrain Control Module (PCM) energizes the relay, which then sends battery voltage to the fuel pump. This allows the pump to pressurize the fuel system before you crank the engine. Once the engine is running, the relay keeps the pump powered so fuel continues to flow to the injectors. A failing relay can cause intermittent starting problems, stalling, or a no-start condition.

Where Is the 2006 Chevy Cobalt Fuel Pump Relay?

The fuel pump relay for the 2006 Cobalt is not under the dash or near the rear seat. Instead, it sits in the engine compartment fuse block, which is the main fuse box located near the battery. Open the hood and look for a black plastic box with a removable cover. The relay is labeled R2 on the inside of the fuse block cover. The cover also lists the fuse and relay functions, so you can confirm you are looking at the right component .

In the 2006 Cobalt fuse diagram, fuse 16 (15A) protects the fuel pump circuit, and relay R2 is the fuel pump relay . If you need to access the relay, simply unclip the cover, locate R2, and pull it straight out with your fingers or a small pair of pliers.

Symptoms of a Failing Fuel Pump Relay

A bad fuel pump relay on a 2006 Cobalt will often mimic a failing fuel pump. Watch for these warning signs:

  1. No fuel pump prime noise – When you turn the key to the ON position (without cranking), you should hear a brief whirring sound from the rear of the car. If you hear nothing, the relay may not be sending power to the pump.
  2. Engine cranks but won’t start – The starter turns the engine over, but the engine never fires because no fuel is being delivered.
  3. Intermittent stalling – The car may run fine for a while, then suddenly lose power and stall. After a few minutes, it may restart again. This is a classic sign of a relay with worn contacts.
  4. No check engine light activity – In many cases, a dead relay will not trigger a check engine light, because the PCM may not detect the electrical fault.
  5. Slow acceleration or sputtering – If the relay is making poor contact, the pump may receive inconsistent voltage, causing the engine to hesitate or lose power under load.

Keep in mind, however, that these same symptoms can be caused by a clogged fuel filter, a dead fuel pump, or even a bad ignition switch. That is why testing the relay first is a smart move—it is fast, cheap, and takes less than ten minutes.

How to Test the Fuel Pump Relay

Testing the relay is a straightforward process that requires a digital multimeter (DMM) and, optionally, a 12V power source. Here is how to do it:

Step 1: Locate the relay and remove it. Pull relay R2 out of the fuse block. The relay is a small, cube-shaped component with either four or five prongs on the bottom.

Step 2: Check the relay coil resistance. Set your multimeter to ohms (Ω). Touch the leads to the two coil terminals (usually terminals 85 and 86). A good relay will show a resistance reading between 50 and 120 ohms. If you get an open circuit (infinite resistance), the coil is burned out and the relay needs to be replaced.

Step 3: Test the switch contacts. With the relay unpowered, check for continuity between terminals 30 and 87A (if present). There should be continuity. Then check between terminals 30 and 87—there should be no continuity when the relay is not energized.

Step 4: Apply power to the coil. Connect 12V to the coil terminals (85 and 86). You should hear a distinct click as the relay energizes. With power applied, check continuity between terminals 30 and 87. Now there should be continuity. If the relay clicks but does not pass current through the switch contacts, replace it.

Step 5: Swap in a known-good relay. If you do not have a multimeter handy, the easiest test is to pull the fuel pump relay and swap it with an identical relay from the same fuse block (such as the starter relay or a spare relay, if available). If the car starts after the swap, the original relay is bad .

Replacement Part Number and Cost

The OEM part number for the 2006 Chevy Cobalt fuel pump relay is 13503102. This relay is gray and green in color and is also used in other GM vehicles. It replaces several earlier part numbers, including 12193604, 15328864, and 12177236 . The relay is a genuine GM component, so it is covered by the factory warranty when you purchase it from an authorized dealer or parts retailer.

The price for this OEM relay is very affordable. At one GM parts dealer, the relay is listed at $7.74, down from an MSRP of $16.90—a 55% savings . Another source lists the same part as a genuine GM relay, also competitively priced . Shipping is typically fast, and most retailers offer a hassle-free return policy.

How to Replace the Fuel Pump Relay

Replacing the relay is one of the easiest repairs you can do on a 2006 Cobalt. Unlike the fuel pump itself—which requires dropping the fuel tank or accessing it through the rear seat—the relay is right on top of the engine bay. Here is a step-by-step guide:

  1. Turn the ignition off and open the hood. Disconnect the negative battery cable to eliminate any risk of accidental sparks .
  2. Remove the fuse block cover. Press the release tabs and lift the cover off. Set it aside.
  3. Locate relay R2. Refer to the diagram on the underside of the cover to confirm the position .
  4. Pull the relay straight out. Grip it firmly with your fingers. If it is stuck, use a small pair of needle-nose pliers on the plastic body—do not pull on the wires.
  5. Inspect the relay socket. Look for signs of corrosion, burnt contacts, or melted plastic. If the socket is damaged, the relay may not make good contact, and you may need to replace the fuse block or have it repaired.
  6. Install the new relay. Align the prongs with the socket and push down firmly until it seats. The relay should sit flush with the fuse block.
  7. Reconnect the battery and turn the key to the ON position. Listen for the fuel pump prime. If you hear the pump whir for a couple of seconds, the relay is working .
  8. Start the engine and verify there are no leaks or issues at the fuse box.

That is all there is to it. The entire job takes about ten minutes and requires no special tools beyond a pair of pliers.

Important: Check Fuse 16 First

Before you replace the relay, take one more step. Check fuse 16 (15A) in the same fuse block, as it protects the fuel pump circuit . If the fuse is blown, the relay will be fine but the pump will still not receive power. A blown fuse usually indicates a short somewhere in the fuel pump wiring, so if you find one, you may need to inspect the wiring harness under the car before you replace the fuse. Replacing a fuse that keeps blowing will just lead to another failure down the road.

Fuel Pump Relay vs. Fuel Pump: How to Tell the Difference

Many owners assume a no-start condition means the fuel pump is dead, but the relay is often the culprit. Here are some ways to tell which component is at fault:

  • If the fuel pump never primes (no sound from the rear of the car when you turn the key), test the relay first. It takes two minutes. If the relay clicks and passes voltage, move on to testing the pump.
  • If the fuel pump runs but the car still won’t start, you likely have a different issue—possibly a clogged fuel filter, a bad fuel pressure regulator, or a failing pump that cannot build pressure.
  • If the car stalls after running for a while and then won’t restart until it cools down, this points to a failing relay, not a pump. Heat causes the relay contacts to expand and lose connection.
  • If the pump makes a loud whining noise, the pump itself is struggling and may need replacement soon, regardless of relay health .

Remember, a fuel pump typically lasts well over 100,000 miles, but running the tank low repeatedly shortens its life . Keep your tank at least a quarter full to help the pump stay cool and lubricated .

Preventive Maintenance Tips

To avoid getting stranded by a fuel system issue, follow these simple habits:

  1. Keep the fuel tank at least a quarter full at all times. Running the tank dry causes the pump to overheat and suck in sediment from the bottom of the tank .
  2. Replace the fuel filter on schedule. A clogged filter makes the pump work harder and can lead to premature failure .
  3. Listen for changes. If you notice a new whining sound from the fuel tank, get the system checked before the pump fails completely .
  4. Test the relay annually. A relay is a wear item. Pull it out, check the contacts for corrosion, and test it with a multimeter if you are comfortable doing so.

Best Fuel Pump Upgrade for Your 2006 Chevy Cobalt: KEMSO

If your testing reveals that the fuel pump itself is failing—or if you simply want to upgrade to a more reliable unit—consider a high-performance replacement from KEMSO. KEMSO is recognized as the US #1 aftermarket fuel pump manufacturer for cars, motorcycles, ATVs, and UTVs . Their fuel pumps are built to meet or exceed OEM specifications, ensuring a perfect fit and dependable performance for your vehicle .

KEMSO fuel pumps are available at a very reasonable price of $79.98—often less than half the cost of dealer parts . Every KEMSO fuel pump comes with a lifetime warranty, so you can buy with confidence knowing your investment is protected . In the rare event of a manufacturing defect, KEMSO will replace the pump at no cost . This warranty covers a wide range of vehicles, including cars, motorcycles, ATVs, UTVs, and personal watercraft .

Some of KEMSO’s top-selling units include pumps for the Subaru Impreza (1998-2023), Honda CBR1000RR (2017-2026), Kawasaki Jet Ski Ultra 310LX (2020-2023), and BMW R1200GS Adventure (2006-2014) . KEMSO also carries pumps for many other popular models, including the Honda Civic Del Sol (1993-1997), KTM 1190 Adventure, and Can-Am Defender HD10 . Whether you drive a car, truck, motorcycle, or watercraft, KEMSO has a fuel pump that will fit your application.

To browse the full catalog and find the right KEMSO fuel pump for your vehicle, visit their website at https://www.kemsoracing.com/ . The site features detailed fitment information, customer reviews, and technical support, making it easy to order with confidence .

Final Thoughts

The 2006 Chevy Cobalt fuel pump relay is a small but critical component. When it fails, your car will crank but not start, and you may be left stranded. Fortunately, the relay is easy to locate in the engine compartment fuse block, quick to test, and inexpensive to replace—the OEM part (13503102) costs about $8 . Always check fuse 16 before swapping the relay, and use a multimeter or a known-good relay to confirm the diagnosis .

If the problem turns out to be the fuel pump itself, skip the cheap knock-offs and choose a KEMSO fuel pump with a lifetime warranty. At just $79.98, it is a smart investment that will keep your Cobalt running reliably for years to come . For the best selection of aftermarket fuel pumps, visit https://www.kemsoracing.com/ today.


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