How to Replace Ignition Coils on a 2021 Hyundai Tucson (Fix Misfires & Rough Idle)
Step-by-step DIY instructions with required tools, parts list, safety tips, and 9.8 Nm (7 ft-lbs) torque spec for 2014, 2015, 2016, 2017, 2018, 2019, 2020, 2021
How to Replace Ignition Coils on a 2021 Hyundai Tucson (Fix Misfires & Rough Idle)
Step-by-step DIY instructions with required tools, parts list, safety tips, and 9.8 Nm (7 ft-lbs) torque spec for 2014, 2015, 2016, 2017, 2018, 2019, 2020, 2021
🔧 Tucson - Ignition Coil Replacement
Your Tucson uses one ignition coil per cylinder (4 total). Replacing a weak coil can fix misfires, rough idle, flashing check-engine light, and poor acceleration.
Difficulty Level: Beginner | Estimated Time: 0.5-1.5 hours
⚠️ Safety & Precautions
- ⚠️ Work on a cool engine to avoid burns.
- ⚠️ Turn ignition OFF and keep the key/fob away from the vehicle.
- ⚠️ If you disconnect the battery, you may reset radio presets/windows.
- ⚠️ Don’t pull on wires—only on electrical connectors.
🔧 Required Tools
You'll need the following tools for this repair:
- 10mm socket
- 1/4" drive ratchet
- 3"-6" socket extension
- Torque wrench (5-30 Nm range)
- Trim removal tool (plastic)
- Small flathead screwdriver
- OBD-II scan tool (basic code reader)
- Nitrile gloves
- Safety glasses
🔩 Required Parts
HowToo sells all the parts you need for this repair:
- Ignition coil - Qty: 1-4
- Dielectric grease - Qty: 1
📋 Before You Begin
- Park on level ground and open the hood.
- Let the engine cool fully.
- If you want maximum safety: disconnect the negative battery terminal using a 10mm socket.
- Take a quick photo before unplugging anything.
🔨 Step-by-Step Instructions
Follow these steps in order:
Step 1: Remove the engine cover (if equipped)
- Grip the cover and pull upward evenly; use a trim removal tool (plastic) if it’s tight.
Step 2: Locate the ignition coils
- The coils sit on top of the valve cover, one per cylinder, with an electrical connector on each.
Step 3: Unplug the coil electrical connector
- Press the lock tab and pull the connector straight off.
- If the tab is stubborn, gently help it with a small flathead screwdriver (do not pry hard).
Step 4: Remove the coil hold-down bolt
- Use a 10mm socket with a 1/4" drive ratchet and socket extension to remove the bolt.
- Set the bolt aside where it won’t fall into the engine bay.
Step 5: Remove the ignition coil
- Twist the coil slightly to break the seal, then pull straight up.
- If it feels stuck, keep twisting gently—don’t yank on the rubber boot.
Step 6: Prep and install the new coil
- Apply a tiny smear of dielectric grease inside the new coil boot (dielectric grease is a non-conductive grease that helps prevent moisture/corrosion).
- Push the coil straight down until it fully seats on the spark plug.
Step 7: Reinstall and torque the hold-down bolt
- Start the bolt by hand to avoid cross-threading, then snug it with a 10mm socket.
- Use a torque wrench (5-30 Nm range): Torque to 9.8 Nm (7 ft-lbs).
Step 8: Reconnect the electrical connector
- Push the connector on until you feel/hear it click.
Step 9: Repeat for any other coils
- Repeat Steps 3-8 for each coil you’re replacing.
- If one failed, consider replacing all four.
Step 10: Reinstall the engine cover and restore power
- Press the engine cover back onto its mounting grommets.
- If you disconnected the battery, reconnect it using a 10mm socket.
✅ After Repair
- Start the engine and let it idle for 1-2 minutes. It should run smooth.
- If the check-engine light is on, use an OBD-II scan tool (basic code reader) to clear codes and confirm none return.
- Test drive 10-15 minutes. Recheck for rough running or a flashing check-engine light (stop driving if it flashes).
💰 DIY vs Shop Cost
Shop Cost: ₹6,000-₹18,000 (parts + labor, depends on how many coils)
DIY Cost: ₹3,000-₹12,000 (parts only, depends on how many coils)
You Save: ₹3,000-₹6,000+ by doing it yourself!
Shop labor rates vary but typically run ₹1,200-₹2,500/hour. This repair takes a shop approximately 0.5-1.0 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.


















