How to Replace Ignition Coils on a 2018 Jeep Renegade (Fix Misfire & Rough Idle)
Step-by-step coil swap with required tools/parts, safety tips, and 8 Nm (71 in-lbs) torque spec for 2015, 2016, 2017, 2018
How to Replace Ignition Coils on a 2018 Jeep Renegade (Fix Misfire & Rough Idle)
Step-by-step coil swap with required tools/parts, safety tips, and 8 Nm (71 in-lbs) torque spec for 2015, 2016, 2017, 2018
🔧 Renegade - Ignition Coil Replacement
Ignition coils create the high voltage needed to fire the spark plugs. When a coil gets weak or fails, your Renegade can misfire, run rough, and trigger a flashing check engine light. Replacing coils is a straightforward under-hood job with basic hand tools.
Difficulty Level: Beginner | Estimated Time: 0.5-1.5 hours
⚠️ Safety & Precautions
- ⚠️ Let the engine cool fully; coils sit on a hot cylinder head.
- ⚠️ If the check engine light is flashing, avoid driving; it can damage the catalytic converter.
- ⚠️ Disconnect the negative battery cable to prevent accidental shorts.
- ⚠️ Pull coils straight up; twisting too hard can tear the rubber boot.
🔧 Required Tools
You'll need the following tools for this repair:
- 10mm socket
- 1/4" ratchet
- 6" extension (1/4" drive)
- Torque wrench (inch-pound or low-range Nm)
- Trim clip tool
- Small flathead screwdriver
- Nitrile gloves
- Safety glasses
- Flashlight
🔩 Required Parts
HowToo sells all the parts you need for this repair:
- Ignition coil - Qty: 1-4 Replace all four if high mileage
- Dielectric grease - Qty: 1
- Spark plug set - Qty: 1 Optional but recommended if due
📋 Before You Begin
- Park on level ground, shift to Park, and set the parking brake.
- Open the hood and let the engine cool to the touch.
- Use a 10mm socket to disconnect the negative battery terminal and isolate it so it can’t spring back.
- If you’re chasing a misfire, note which cylinder is misfiring (example: P0302 = cylinder 2). This helps you swap just one coil or test by moving coils.
🔨 Step-by-Step Instructions
Follow these steps in order:
Step 1: Remove the engine cover (if equipped)
- Use a trim clip tool and your hands to lift the cover straight up from its rubber grommets.
- Set it aside where it won’t get stepped on.
Step 2: Locate the ignition coils
- On the 1.4L engine, each coil sits directly on top of a spark plug along the top of the engine.
- One coil per cylinder
Step 3: Unplug the coil electrical connector
- Use a small flathead screwdriver to gently lift the locking tab if it’s tight.
- Press the release and pull the connector straight off (don’t pull on the wires).
Step 4: Remove the coil retaining bolt
- Use a 10mm socket, 1/4" ratchet, and 6" extension to remove the bolt holding the coil to the valve cover.
- Put the bolt somewhere safe; it’s easy to drop.
Step 5: Remove the ignition coil
- Grip the coil body and pull straight upward.
- If it’s stuck, gently wiggle while pulling up—avoid prying hard on plastic.
- The rubber boot seals tight
Step 6: Prep and install the new coil
- Put a very small dab of dielectric grease inside the tip of the new coil boot.
- Push the new coil straight down until you feel it fully seat on the spark plug.
Step 7: Reinstall and torque the coil bolt
- Thread the bolt in by hand first to avoid cross-threading.
- Use a torque wrench to tighten the coil bolt: Torque to 8 Nm (71 in-lbs).
Step 8: Reconnect the electrical connector
- Push the connector on until it clicks/locks.
- Gently tug to confirm it’s secure.
Step 9: Repeat for any other coils
- If replacing all coils, repeat Steps 3-8 for each cylinder.
- If diagnosing a misfire, you can swap a suspected coil to another cylinder and see if the misfire “follows.”
Step 10: Reinstall the engine cover and reconnect the battery
- Press the engine cover back onto its grommets by hand.
- Use a 10mm socket to reconnect the negative battery terminal snugly.
✅ After Repair
- Start the engine and let it idle for 1-2 minutes. It should run smooth with no shaking.
- If you had a check engine light, clear codes with a scan tool if available; otherwise it may clear after a few drive cycles if the fault is gone.
- Test drive 10-15 minutes and recheck for warning lights.
- If misfire remains, the issue may be a spark plug, injector, vacuum leak, or wiring at that coil connector.
💰 DIY vs Shop Cost
Shop Cost: $250-$650 (parts + labor)
DIY Cost: $60-$320 (parts only)
You Save: $190-$330 by doing it yourself!
Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 0.7-1.2 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.


















