How to Replace the Fuel Cap on a 2016 Audi A6 (Fix EVAP Leaks & Check Engine Light)
Step-by-step fuel cap replacement with required tools/parts, safety tips, and post-repair checks for 2012, 2013, 2014, 2015, 2016, 2017, 2018
How to Replace the Fuel Cap on a 2016 Audi A6 (Fix EVAP Leaks & Check Engine Light)
Step-by-step fuel cap replacement with required tools/parts, safety tips, and post-repair checks for 2012, 2013, 2014, 2015, 2016, 2017, 2018
🔧 A6 - Fuel Cap Replacement
Replacing the fuel cap is a quick job that helps prevent fuel vapor leaks and check-engine lights caused by an improper seal. On your A6, the cap is a simple screw-on style behind the fuel door, usually with a small tether (strap) to keep it from getting lost.
Difficulty Level: Beginner | Estimated Time: 0.1-0.2 hours
⚠️ Safety & Precautions
- ⚠️ Work outside or in a well-ventilated area; fuel vapors are flammable.
- ⚠️ No smoking, sparks, or open flames near the fuel door.
- ⚠️ Let the car cool down if it was just driven (hot parts + vapors).
- ⚠️ Battery disconnect is not required for this repair.
🔧 Required Tools
You'll need the following tools for this repair:
- Nitrile gloves
- Shop towel
- Plastic trim tool set
- Flashlight
- Safety glasses
🔩 Required Parts
HowToo sells all the parts you need for this repair:
- Fuel cap (OEM-style, sealing type) - Qty: 1
📋 Before You Begin
- Park on level ground and turn the engine off.
- Unlock the car so the fuel door will open normally.
- Wipe dirt around the cap area using a shop towel so nothing falls into the filler neck (the metal/plastic tube you fuel through).
🔨 Step-by-Step Instructions
Follow these steps in order:
Step 1: Open the fuel door
- Press the fuel door to pop it open (car must be unlocked).
- Use a flashlight to check the area for dirt or damage.
Step 2: Remove the old fuel cap
- Turn the cap counterclockwise by hand until it releases.
- Set it where it won’t pick up dirt.
- If it’s tethered, let it hang carefully without twisting the strap.
Step 3: Inspect and clean the sealing surfaces
- Use a shop towel to wipe the filler neck sealing lip (the smooth ring where the cap seals).
- Check the old cap’s rubber seal (gasket) for cracks or flattening. Bad seals cause EVAP leaks.
Step 4: Install the new fuel cap
- Thread the new cap on by hand clockwise.
- Tighten until you feel/hear it click (most OEM-style caps click when fully seated). Hand tight only.
Step 5: Close the fuel door
- Close the fuel door firmly until it latches.
- Wipe off any fingerprints or fuel residue using a shop towel.
✅ After Repair
- Start the engine and confirm there’s no fuel smell around the fuel door.
- If you had a check-engine light from a loose cap, it may take a few drive cycles to clear on its own.
- If the light remains on, scan for codes—an EVAP leak can also be caused by other hoses/valves.
💰 DIY vs Shop Cost
Shop Cost: $40-$120 (parts + labor)
DIY Cost: $15-$45 (parts only)
You Save: $25-$75 by doing it yourself!
Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 0.1-0.2 hours.
🎯 Ready to get started?
HowToo makes it easy: same-day/2-day shipping on every part, plus all the tools and specialty tools you need! Check out the parts and tools sections below to add everything to your cart.


















