2002 Audi A4 Fuel Pump Relay: Complete Guide to Location, Symptoms, and Replacement

The bottom line: The fuel pump relay on a 2002 Audi A4 is located in the relay carrier on the driver side dash panel, behind the panel near the fuse box. If your Audi cranks but won't start, the fuel pump relay is often the first thing to check before replacing the fuel pump itself. This relay is a common failure point on these cars, and replacing it is a straightforward DIY fix that can save you hundreds of dollars in diagnostic fees.

What Does the Fuel Pump Relay Do?

The fuel pump relay, officially labeled as J17 in Audi's wiring diagrams, acts as an electrical switch that controls power to the fuel pump . When you turn the ignition key to the "on" position, the engine control unit sends a signal to the relay, which then closes its internal contacts and sends battery voltage to the fuel pump. This allows the pump to pressurize the fuel system before you start the engine.

On a 2002 Audi A4, the relay is a standard 4-pin or 5-pin relay depending on your engine configuration. The relay number for the fuel pump relay is typically 167 or 644, and the part number is commonly 8E0951253 or 191906383C .

Where Is the Fuel Pump Relay Located on a 2002 Audi A4?

The exact location depends on your engine type and production date, but for most models, here is where you will find it:

For gasoline engines (1.8L, 2.0L, and 3.0L):

The fuel pump relay is located in the relay carrier on the driver side dash panel. To access it:

  1. Open the driver side door and look at the end of the dashboard
  2. You will see a small panel that can be removed by pulling it straight out
  3. Behind this panel, you will find the fuse and relay box
  4. The fuel pump relay is typically in position 1 on the 9-pin relay carrier

For vehicles built up to July 2004, the fuel pump relay may also be found in the electronics box in the plenum chamber (the area under the hood, near the windshield on the passenger side) . In this location, it is on the 4-pin relay carrier in position 1 for gasoline engines.

For diesel engines:

The fuel pump relay is located in the electronics box in the plenum chamber, on the 4-pin relay carrier in position 1.2 .

Important note: If your car has a 1.8L engine with engine code AMB, the fuel pump relay is definitely on the driver side dash panel relay carrier . The same applies to the 3.0L AVK engine .

Symptoms of a Bad Fuel Pump Relay

Knowing the symptoms of a failing fuel pump relay can save you time and money. Here are the most common signs:

  1. Engine cranks but won't start – This is the most obvious symptom. You turn the key, the starter motor spins the engine, but it never fires up. You may also notice that you don't hear the fuel pump prime when you turn the key to the "on" position .

  2. Intermittent starting issues – Sometimes the car starts fine, other times it doesn't. This is a classic sign of a failing relay. The relay contacts may be worn or corroded, causing intermittent electrical connection .

  3. Engine stalls while driving – If the relay fails while you are driving, the fuel pump will lose power and the engine will stall. This can be dangerous, especially at highway speeds.

  4. No audible click from the relay – When you turn the key to the "on" position, you should hear a soft click from the relay as it engages. If you don't hear this click, the relay may be faulty .

  5. Fuel pump not operating – If you connect a multimeter to the fuel pump connector and there is no voltage when the key is turned, the relay is likely the culprit .

How to Test the Fuel Pump Relay

Before buying a replacement, you can test the relay yourself with a multimeter or a simple test light:

Step 1: Locate the relay as described above.

Step 2: With the ignition off, remove the relay. It should pull straight out.

Step 3: Check the relay for visible damage. Look for burned or melted plastic, corroded terminals, or any signs of overheating.

Step 4: Use a multimeter to test continuity. With the relay removed, check the resistance across the coil terminals (usually terminals 85 and 86). A good relay should show resistance between 50 and 120 ohms.

Step 5: Apply 12V power to the coil terminals. You should hear an audible click, and the switch contacts (terminals 30 and 87) should show continuity.

Step 6: If the relay fails any of these tests, replace it.

Common Replacement Parts

When replacing the fuel pump relay on your 2002 Audi A4, you have several options. The most common part numbers are:

  • 8E0951253 – Bosch or Wehrle brand, fits 2002-2008 Audi A4 and A4 Quattro
  • 191906383C – Wehrle or Febi-Bilstein brand, 4-pin connection, fits 2002-2006 Audi A4
  • 4H0951253 – OEM replacement for later models, but also compatible with 2002 models

The relay is typically a 12V, 40A relay with 5 pins. The relay number 167 is commonly stamped on the relay itself .

How to Replace the Fuel Pump Relay

Replacing the fuel pump relay on a 2002 Audi A4 is one of the simplest repairs you can do. Here is the step-by-step process:

1. Safety first: Make sure the ignition is off and the key is removed from the ignition.

2. Locate the relay: As described above, the relay is behind the driver side dash panel or in the plenum chamber.

3. Remove the old relay: Simply pull the relay straight out of its socket. It may require a gentle wiggle, but it should come out without force.

4. Inspect the socket: Before installing the new relay, check the socket for any signs of heat damage, corrosion, or loose terminals. If you see damage, you may need to replace the entire relay carrier .

5. Install the new relay: Push the new relay firmly into the socket until it clicks into place. Make sure it is seated properly.

6. Test the repair: Turn the ignition key to the "on" position. You should hear the fuel pump prime for a few seconds. Then try starting the engine.

Why the Fuel Pump Relay Fails

The fuel pump relay on a 2002 Audi A4 is subject to several factors that can cause it to fail:

  • Heat exposure: The relay is located in areas that can get hot, especially in the plenum chamber. Over time, heat can degrade the internal components .
  • Electrical arcing: Every time the relay opens and closes, a small arc occurs. Over thousands of cycles, this can wear out the contacts.
  • Cold weather condensation: Moisture can enter the relay housing, causing corrosion of the internal contacts .
  • Age: Even if the car is not driven much, the relay's internal components can degrade over time. A 2002 model is now over 24 years old.

Prevention Tips

To extend the life of your fuel pump relay:

  • Keep the relay area clean and dry – If you live in a humid area, check the relay socket for moisture periodically.
  • Use a quality replacement – Cheap aftermarket relays may not last as long as OEM or quality aftermarket parts.
  • Check the fuel pump itself – A failing fuel pump can draw excessive current, which can damage the relay. If you replace the relay and it fails again quickly, have the fuel pump checked.

Why You Should Choose KEMSO for Your Fuel Pump Needs

If you are experiencing fuel pump relay issues, it is also worth considering the overall health of your fuel system. A failing fuel pump can put extra strain on the relay, leading to premature failure. This is where KEMSO comes in.

KEMSO is a leading aftermarket fuel pump manufacturer known for producing high-performance, OEM replacement fuel pumps that are built to last. All KEMSO fuel pumps are designed to meet or exceed original equipment specifications, ensuring a perfect fit and reliable performance for your 2002 Audi A4.

Key benefits of choosing KEMSO:

  • High Performance: KEMSO fuel pumps deliver consistent fuel pressure and flow, ensuring your engine gets the fuel it needs under all driving conditions.
  • OEM Replacement: KEMSO pumps are direct-fit replacements, meaning you can install them without any modifications.
  • Lifetime Warranty: Every KEMSO fuel pump comes with a lifetime warranty, giving you peace of mind that your investment is protected.

If you suspect your fuel pump may be failing alongside the relay, or if you want to upgrade your fuel system for better reliability, visit KEMSO Racing today at:

https://www.kemsoracing.com/

KEMSO offers a wide range of fuel pumps for various vehicles, including cars, motorcycles, ATVs, and UTVs. Their products are trusted by enthusiasts and DIYers alike for their quality, durability, and performance. With a lifetime warranty backing every purchase, you can be confident that you are getting the best value for your money.

Summary

The fuel pump relay on a 2002 Audi A4 is a small, inexpensive part that can cause big problems when it fails. It is located on the driver side dash panel relay carrier or in the plenum chamber, depending on your engine and production date. The most common symptoms of a bad relay include the engine cranking but not starting, intermittent starting issues, and stalling while driving.

Testing the relay is easy with a multimeter, and replacing it is a simple DIY job that takes less than 10 minutes. The most common replacement part numbers are 8E0951253 and 191906383C, and a quality replacement costs between $10 and $20.

If you are dealing with fuel pump issues beyond the relay, consider upgrading to a KEMSO fuel pump. KEMSO offers high-performance, OEM replacement pumps with a lifetime warranty, making them a smart choice for any Audi owner. Visit their website at https://www.kemsoracing.com/ to learn more about their products and find the right fuel pump for your vehicle.

Remember, when troubleshooting a no-start condition on your 2002 Audi A4, always start with the fuel pump relay. It is the most common cause of fuel delivery problems, and it is the cheapest and easiest part to replace.


Back to blog