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Audi A3/A4 B7: How to Replace Spark Plugs and Ignition Coils

Your spark plugs and ignition coils wear down over time until they eventually fail to spark. This article shows you how to replace worn out spark plugs and ignition coils.

By Jared Hammond - March 25, 2016

This article applies to the Audi A3 and A4 B7 (2003-2008).

It's important to replace your spark plugs and ignition coils as part of your Audi's regular maintenance. Worn out spark plugs and ignition coils can lead to engine misfires and could eventually damage your engine. If you're getting a check engine light for engine misfires, it's time for some new plugs and coils. Replacing the spark plugs and ignition coils is a relatively simple task and requires no mechanical expertise.

Audi A3/A4 B7: How to Replace Spark Plugs and Ignition Coils

Materials Needed

  • Replacement spark plugs and/or ignition coils
  • Ratchet with extension
  • 5/8" spark plug socket
  • Torque wrench
  • T20 and T25 Torx screwdrivers
  • Flat head screwdriver
  • Spark plug gap checker

Before you begin, remember to disconnect your battery whenever you're working on an electrical or ignition related system. Additionally, the engine must be cold when removing plugs. Attempting to remove or install plugs in a hot engine could result in permanently damaging the head cylinder if you strip any threads.

Step 1 – Remove the engine cover

This applies to the Audi A3. Disconnect the MAF and turbo inlet connectors. Remove the two Torx screws near the air filter. Then pry the engine cover off starting from the back of the engine.

audi a3 a4 b7 2.0t engine spark plug igntion coil replace remove change how to
Figure 1. Remove the engine cover.

Step 2 – Remove the ignition coils and spark plugs

The ignition coils are easy to identify, as they are lined up in a row on the passenger side on an Audi A4, or along the back in the Audi A3. The ignition coils are plugged into a wiring harness. Remove the two screws holding down the wiring harness. Then use your flat head screwdriver to push in the clips of each plug to loosen the plug from the ignition coil. Repeat this for each plug. Now all you need to do is pull the ignition coils out of the engine. You may need to wiggle them out, but they should come loose.

audi a3 a4 b7 2.0t engine spark plug igntion coil replace remove change how to
Figure 2. Unplug and remove the ignition coils.

At the bottom of each ignition coil well there will be a spark plug. Use your ratchet with a spark plug socket and extension to loosen as well as remove the spark plugs.

audi a3 a4 b7 2.0t engine spark plug igntion coil replace remove change how to
Figure 3. Remove the spark plugs.

Step 3 – Install new spark plugs and ignition coils

Remember to check the gaps on your spark plugs to make sure they are the correct spec for your engine. Most likely you will not need to adjust them, but if you must, you can gently tap the end of the spark plug with a blunt instrument until it fits. Installation is the reverse of the previous step. Thread in the new spark plug by hand, then tighten it with a torque wrench to 22 ft-lbs.

audi a3 a4 b7 2.0t engine spark plug igntion coil replace remove change how to
Figure 4. Check the gap on your spark plugs.

Insert the new ignition coil until it snaps into place. Once all the ignition coils are installed, plug in the wiring harness and tighten down the two mounting screws. Reattach the engine cover if needed, then reconnect the battery. Start the engine and be watchful for any misfires. Take it out for a test drive and observe how the engine runs. If a misfire is no longer detected, the check engine light should eventually shut off by itself.

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