How to Replace the Fuel Cap on a 2018 Hyundai Kona (Fix EVAP Leak & Check Engine Light)
Step-by-step DIY instructions, required tools/parts, safety tips, and what to do if P0455/P0456 returns
How to Replace the Fuel Cap on a 2018 Hyundai Kona (Fix EVAP Leak & Check Engine Light)
Step-by-step DIY instructions, required tools/parts, safety tips, and what to do if P0455/P0456 returns
🔧 Kona - Fuel Cap Replacement
Replacing your Kona’s fuel cap is a quick job, but it matters because a weak seal can trigger an EVAP leak code (like P0455/P0456) and turn on the check engine light. You’ll remove the old cap, confirm the seal surface is clean, and install the correct replacement cap so it clicks tight.
Difficulty Level: Beginner | Estimated Time: 0.1-0.2 hours
⚠️ Safety & Precautions
- ⚠️ Work with the engine OFF and away from sparks/flames.
- ⚠️ Do not top off fuel after the pump clicks off.
- ⚠️ If you smell strong fuel odor or see fuel leakage, stop and don’t drive until it’s addressed.
- ⚠️ Battery disconnect is not required.
🔧 Required Tools
You'll need the following tools for this repair:
- Nitrile gloves
- Safety glasses
- Clean shop towel
- Flashlight
🔩 Required Parts
HowToo sells all the parts you need for this repair:
- Fuel cap (capless-style not used on your Kona) - Qty: 1
- Fuel cap tether (if damaged, optional) - Qty: 1
📋 Before You Begin
- Park on level ground and shift to Park.
- Turn the engine off and remove the key/fob from the vehicle.
- Open the fuel door using the exterior fuel door (push-to-open) and confirm the area is clean.
🔨 Step-by-Step Instructions
Follow these steps in order:
Step 1: Open the fuel door and remove the old cap
- Put on nitrile gloves and safety glasses.
- Open the fuel door and turn the fuel cap counterclockwise until it releases.
- Let the cap hang by the tether (the little strap/cable that keeps it from falling).
Step 2: Inspect and clean the sealing surface
- Use a flashlight to look at the filler neck sealing surface (the round rim where the cap seals).
- Wipe the rim with a clean shop towel to remove dust or grit.
- Grit on the rim can cause EVAP leaks.
Step 3: Install the new fuel cap
- Thread the new cap on by hand, turning clockwise.
- Tighten until you hear/feel at least 1–3 clicks (the cap’s built-in clutch prevents overtightening).
- If the tether is part of the cap, make sure it’s routed the same way as the old one and doesn’t bind.
Step 4: Close up
- Close the fuel door firmly.
- Wipe any fuel residue with the clean shop towel.
✅ After Repair
- Start your Kona and confirm there’s no fuel smell.
- If you had a check engine light from a loose/bad cap, it may take several drive cycles to turn off on its own.
- If the light stays on after a few days of normal driving, you may need a scan to confirm whether another EVAP leak exists.
💰 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.

















