How to Replace Ignition Coils on a 2018 Jeep Compass (Fix Misfire & Rough Idle)
Step-by-step coil-on-plug replacement with required tools, parts, safety tips, and 9 Nm (80 in-lb) torque spec for 2017, 2018, 2019, 2020, 2021, 2022
How to Replace Ignition Coils on a 2018 Jeep Compass (Fix Misfire & Rough Idle)
Step-by-step coil-on-plug replacement with required tools, parts, safety tips, and 9 Nm (80 in-lb) torque spec for 2017, 2018, 2019, 2020, 2021, 2022
đź”§ Compass - Ignition Coil Replacement
Your Compass uses a coil-on-plug setup (each spark plug has its own ignition coil). Replacing a bad coil fixes common issues like misfires, rough idle, and flashing check engine light.
Difficulty Level: Beginner | Estimated Time: 0.5-1.5 hours
⚠️ Safety & Precautions
- ⚠️ Let the engine cool completely before starting (burn risk).
- ⚠️ Disconnect the negative battery cable to prevent accidental short circuits.
- ⚠️ Pull ignition coils straight up—don’t yank the wiring harness.
- ⚠️ Keep dirt out of the spark plug wells (the deep holes the coils sit in).
đź”§ Required Tools
You'll need the following tools for this repair:
- 10mm socket
- 1/4" drive ratchet
- 6" socket extension
- Torque wrench (in-lb or low-range Nm)
- Flathead screwdriver
- Trim clip removal tool
- Needle-nose pliers
- Shop rags
- Nitrile gloves
- Safety glasses
🔩 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 Non-conductive grease for boots
đź“‹ Before You Begin
- Park on level ground, set the parking brake, and open the hood.
- If you have a check engine light, write down which cylinder misfires (if known) before disconnecting the battery.
- Disconnect the battery: use a 10mm socket to remove the negative (-) terminal and tuck it aside.
🔨 Step-by-Step Instructions
Follow these steps in order:
Step 1: Remove the engine cover (if equipped)
- Grip the cover and pull upward to release the rubber grommets, or remove any fasteners using a trim clip removal tool.
- Set the cover aside where it won’t get stepped on.
Step 2: Make room to reach the coils (as needed)
- If the air intake duct blocks access, loosen the clamp(s) using a flathead screwdriver.
- Release any push-clips with a trim clip removal tool, then lift the duct out of the way.
Step 3: Unplug the ignition coil electrical connector
- Find the ignition coils along the top of the engine.
- Press the connector lock tab and pull the connector straight off. Use needle-nose pliers only if needed, and pull on the connector body (not the wires).
Step 4: Remove the ignition coil hold-down bolt
- Use a 10mm socket, 6" socket extension, and 1/4" drive ratchet to remove the coil’s hold-down bolt.
- Set the bolt aside so it doesn’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 the boot feels stuck, keep twisting while pulling—don’t pry on the valve cover.
- Check the spark plug well for oil or water using a flashlight (if you have one). If you see fluid, stop and clean/diagnose before installing the new coil.
Step 6: Install the new ignition coil
- Apply a tiny smear of dielectric grease inside the coil boot. (Dielectric grease is a silicone grease that helps prevent moisture and makes future removal easier.)
- Push the coil straight down until it fully seats onto the spark plug.
Step 7: Reinstall the hold-down bolt and torque it
- Start the bolt by hand first (prevents cross-threading).
- Use a torque wrench (in-lb or low-range Nm) to tighten the coil bolt: Torque to 9 Nm (80 in-lbs).
Step 8: Reconnect the electrical connector
- Push the connector on until it clicks/locks.
- Give it a gentle tug to confirm it’s fully latched.
Step 9: Repeat for any other coils you’re replacing
- Replace coils one at a time so connectors don’t get mixed up.
Step 10: Reinstall the intake duct and engine cover
- Reinstall the intake duct and tighten clamps using a flathead screwdriver.
- Reinstall the engine cover by pressing it down onto the grommets.
Step 11: Reconnect the battery
- Reinstall the negative (-) battery terminal using a 10mm socket.
âś… After Repair
- Start the engine and let it idle for 1-2 minutes. It should run smooth with no shaking.
- Test drive for 10 minutes and confirm the check engine light stays off.
- If the check engine light was on, you may need to clear codes with a scan tool after the repair.
- If the misfire returns, the next common checks are spark plugs, plug tube oil, and wiring/connectors.
đź’° DIY vs Shop Cost
Shop Cost: $250-$450 (parts + labor)
DIY Cost: $80-$260 (parts only)
You Save: $170-$190 by doing it yourself!
Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 0.8-1.2 hours.
🎯 Ready to get started?
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