2006 Audi A6 Fuel Pump Relay Location: The Complete Owner's Guide

The bottom line: On a 2006 Audi A6 (C6 generation, 2004–2011), the fuel pump relay (J17) is not located in the interior fuse panel. It sits inside the electronics box in the plenum chamber on the driver's side of the engine compartment, beneath the windshield cowl, typically under the ECU. For 3.2L V6 engines, the relay is often a black cube marked "614," and there is a second relay position for diesel models. If your car cranks but won't start, the fuel pump relay is one of the first things to check, but you need to know exactly where to look and how to test it.

This guide walks you through the relay locations for both gasoline and diesel 2006 A6 models, how to access the plenum electronics box safely, how to test the relay, and common problems that mimic a failed relay. We'll also cover related components like the fuel pump control module and the fuses that protect the circuit.

Where the Fuel Pump Relay Hides on the 2006 Audi A6

Unlike older Audi models where the fuel pump relay lived behind the dashboard or in the central electric panel, the C6 A6 moved this critical component to the engine compartment. The relay carrier sits in the left plenum chamber (the recessed area under the windshield wiper arms, on the driver’s side). This is the same electronics box that houses the engine control unit (ECU).

The fuel pump relay is designated J17 in Audi workshop manuals. On 3.2L V6 gasoline engines, the relay position is labeled R2 in the relay carrier. For diesel engines (such as the 3.0L TDI with engine codes BMK or BNG), the relay is in position R2.1.

In simpler terms, open the hood. Look at the firewall area on the driver's side. You'll see a black plastic cover running along the base of the windshield. Under that cover is the electronics box. The fuel pump relay is inside, often mounted on a carrier that also holds other relays like the Motronic current supply relay (J271) and the secondary air pump relay.

How to Access the Plenum Electronics Box

Getting to the relay takes about ten minutes with basic hand tools. Here's the step‑by‑step process:

1. Park the car on level ground and turn the ignition off. Open the hood and locate the plastic cowl cover at the base of the windshield on the driver's side. It is held in place by clips or small screws, depending on your build date.

2. Remove the cowl cover. Some models have a rubber seal along the top edge. Gently pull the seal away and unclip the plastic trim. Set it aside without forcing it—the plastic is old and can crack in cold weather.

3. Look for the black electronics box. Under the cowl, you'll see a rectangular black box with a lid secured by screws or metal clips. This is the plenum chamber E‑box. The ECU sits on top inside.

4. Lift the lid. Depending on your car, the lid may have a rubber gasket. If you see water inside the box, that is a serious problem—it means the plenum drains are clogged, and water may have already damaged the relay or other electronics. This is common on the C6 A6, and it's a leading cause of relay failure.

5. Locate the relay. The fuel pump relay J17 is typically a black cube relay, about an inch square, marked with the number 614 on its top face. On the relay carrier, you'll find it in position R2 (gasoline) or R2.1 (diesel).

What About the Other Fuse Boxes?

The 2006 A6 has several fuse and relay boxes, and it's easy to confuse them. Here's a quick map:

Right dash panel fuse box (driver's side instrument panel) — This is where you'll find the fuel pump fuse (a 20A ATO fuse labeled ST2‑12) for certain engine codes like BMK, BNG, BPP, BBJ, BAT, and AUK. If your fuel pump is completely dead, check this fuse first before pulling the relay.

Electronics box, right in plenum chamber — On some models, there is a second electronics box on the passenger side. It contains fuses and relays for other systems, but the fuel pump relay is in the left box, not this one.

Luggage compartment fuse panel — This panel, on the right side behind the trim, contains a fuse (SF1, 20A) for the auxiliary heater fuel pump relay (J749) and the blocking relay (J771). It does not contain the main fuel pump relay.

Relay and fuse carrier on the steering cross member — This panel, under the dash on the driver's side, holds relays for the starter, horn, and terminal 15 power supply. The fuel pump relay is not here on the C6.

Testing the Fuel Pump Relay

A relay is an electromagnetic switch. When the ignition is on, the engine control unit sends a small current through the relay coil, which closes the contacts and sends power to the fuel pump. If the relay fails, the pump gets no power, and the engine will crank but not start.

Before you replace anything, test the relay. Use a digital multimeter:

1. Check for power at the relay socket. With the ignition on, probe the socket terminals. You should see battery voltage (around 12V) at the terminal that supplies the relay coil and at the terminal that feeds the pump contacts.

2. Verify the ground. The relay coil needs a ground signal from the ECU. If the ECU isn't grounding the coil (due to a faulty crank sensor or a wiring issue), the relay won't energize even though it's good.

3. Test the relay itself. Remove the relay and apply 12V across the coil terminals (usually pins 85 and 86). You should hear a distinct click as the contacts close. Then check for continuity across the switch terminals (usually pins 30 and 87) with an ohmmeter. If you hear the click but there's no continuity, the relay is worn and needs replacement.

If you don't have a multimeter, a simple swap test works too. Find another relay in the same box with the same part number (like the Motronic current supply relay) and swap them. If the car starts, your relay was bad.

Common Causes of Fuel Pump Relay Failure

The most frequent reasons the relay stops working include:

1. Current overload — A failing fuel pump motor can draw more current than the relay is rated for, causing the contacts to overheat and burn out.

2. Short circuit — A damaged wire in the pump circuit can cause a surge that destroys the relay's contacts or coil.

3. Water ingress in the plenum — This is a big one on the C6 chassis. The plenum drains under the windshield cowl clog with leaves and debris. Rainwater then collects and submerges the electronics box, causing the relay to short out or corrode. This is why some owners report stalling after driving in the rain or washing the car.

4. Age and vibration — Relay contacts wear out over time from repeated cycling. On a 2006 car, you're dealing with a 20‑year‑old component made of moving parts. Replacement is cheap insurance.

What Else Could Be Wrong If the Car Won't Start?

If the relay checks out fine, the problem may lie elsewhere in the fuel delivery system. Here are the usual suspects, in order of likelihood:

1. The fuel pump control module (J538). On the C6 A6, the fuel pump control module is located under the rear seat bench on the passenger side, mounted in a white bracket. This module controls the variable‑speed fuel pump. It is known to fail, causing intermittent stalling or a no‑start condition. If your relay clicks but the pump doesn't run, test the module before condemning the pump.

2. A blown fuse. The fuel pump fuse (20A) is in the driver's side dash fuse panel. A shorted coil pack or a damaged wire can blow this fuse. Check it visually and with a test light, not just by eye.

3. A clogged fuel filter. A severely restricted filter makes the pump work harder, which can cause it to fail prematurely. If the filter hasn't been changed in 60,000 miles, replace it.

4. The fuel pump itself. If the pump is burned out, the engine will crank but won't fire. You can check for fuel pressure at the rail with a gauge, or simply listen for a humming sound from the rear of the car when you turn the ignition on for two seconds. No hum usually means a dead pump.

5. Wiring issues. Damaged, corroded, or loose wires between the relay, the pump, and the ECU can prevent power from reaching the pump. Look for chafed wires under the car and in the plenum box.

A Special Warning About the Plenum Drains

Because water in the plenum is such a common cause of relay and ECU failure on the C6 A6, take a few minutes to inspect the drains. They are located at both ends of the plenum chamber, under the cowl. Clear away leaves, pine needles, and dirt. If the box has already been submerged, dry it out and inspect every relay and connector for green corrosion. If you see corrosion on the relay socket, replace the socket or the entire relay carrier rather than just plugging in a new relay—the corrosion will quickly kill the new one too.

Replacement Parts and Part Numbers

When you're ready to buy a replacement, here's what you need to know:

• Fuel pump relay (J17) — This is a standard 4‑pin relay. Audi used several part numbers, but the relay is commonly marked "614." You can find it at any auto parts store under the standard relay number if you match the pin layout.

• Fuel pump control module (J538) — The part number is often a variation of 4F0 906 093. This module is mounted under the rear seat on the passenger side.

• Fuel pump — On the 2006 A6, the pump is in‑tank, accessible by removing the rear bench seat. The pump and module assembly is a single unit on some engines.

How to Prevent Future Relay Problems

Prevention is simpler than repair. Here's a short checklist:

1. Clean the plenum drains twice a year — Spring and fall are good times. This one habit prevents the most common electrical failures on this car.

2. Replace the relay proactively — At 20 years old, the relay is at the end of its design life. A new relay costs a few dollars. Replacing it before it fails beats getting stranded.

3. Keep the underside of the cowl dry — Make sure the rubber gasket on the electronics box lid is in good shape and seats properly. If the gasket is cracked or missing, replace it.

4. Use quality parts — Cheap relays from unknown brands are a false economy. Buy a relay from a reputable source, and make sure the pin layout matches the factory relay exactly.

Why You Should Consider a KEMSO Fuel Pump

If your diagnostic work points to a failing fuel pump rather than a relay, it's worth investing in a quality replacement instead of "the cheapest one that fits." The labor to swap the pump on a 2006 A6 is the same whether you install a budget part or a premium one, but the lifespan and reliability are not.

KEMSO specializes in high‑performance fuel pumps that are built as direct OEM replacements. Every KEMSO pump is designed to meet or exceed the original factory specifications, delivering consistent fuel pressure and flow that your A6's engine management system expects. Whether you drive a 2.0T, 3.2 V6, or diesel variant, KEMSO has a pump that fits your application without modifications.

Every KEMSO fuel pump is covered by a lifetime warranty, which means you'll never have to worry about premature pump failure cutting your trip short. For a part buried inside the fuel tank—where labor costs more than the part itself—that piece of mind is worth real money.

Before you buy any fuel pump online, verify your engine code (printed in your owner's manual or on the sticker in the service booklet) and confirm that the replacement pump matches your VIN. That extra minute checking ensures you get the right part the first time.

Visit https://www.kemsoracing.com/ to browse their catalog of fuel pumps for Audi and other vehicles. With thousands of satisfied customers and a lifetime warranty on every pump, KEMSO is a name you can trust under the hood of your German sedan.

Final Thoughts

The fuel pump relay on a 2006 Audi A6 is a small part with a big job. When it fails, your car becomes a lawn ornament in the driveway. But now you know exactly where it hides—inside the plenum electronics box on the driver's side, under the windshield cowl—and how to test it, replace it, and prevent it from failing again.

If your problem turns out to be the pump itself, don't settle for a no‑name part. Choose a KEMSO fuel pump for performance, reliability, and lifetime coverage. Find yours at https://www.kemsoracing.com/ today.