Ignition Coils - All

This procedure covers the replacement of all four ignition coils on the 2018-2024 Honda Accord 1.5L turbocharged engine, including removal of the engine cover and disconnecting the coil connectors.

Warnings

Tools required

Parts

• Ignition coil × 4 — Honda 30520-5AA-A02 or equivalent
• Spark plug × 4 — NGK DILKAR8A8S or equivalent (optional replacement)

Preparation

1. Park vehicle on level surface and engage parking brake
2. Turn ignition off and remove key from vehicle
3. Allow engine to cool for at least 30 minutes if recently operated
4. Open hood and secure with prop rod

Procedure

1. 1

   Remove engine cover
   Grasp the engine cover firmly and pull upward to disengage the rubber grommets from the mounting posts. The cover is held only by friction-fit grommets and does not require tools for removal. Set the cover aside in a clean area.
2. 2

   Disconnect ignition coil electrical connectors
   Locate all four ignition coil electrical connectors on top of the engine. Press down on the locking tab of each connector while pulling the connector away from the coil. Work carefully to avoid breaking the locking tabs. If connectors are tight, gently rock them side-to-side while pulling.
3. 3

   Remove ignition coil mounting bolts
   Using a 10mm socket with extension, remove the single mounting bolt from each of the four ignition coils. The bolts are located at the top center of each coil. Keep bolts organized for reinstallation.
   Torque spec

   Ignition Coil Bolts8 Nm (6 lb-ft)
4. 4

   Extract ignition coils from cylinder head
   Grasp each ignition coil firmly and pull straight up with steady pressure. The coil boots may be stuck to the spark plugs due to heat cycling. If a coil resists removal, gently twist it clockwise and counterclockwise while pulling upward. Do not use excessive force or pry tools as this can damage the boot or spark plug terminal.
   ⚠Inspect each coil boot for tears or damage during removal. Damaged boots must be replaced to prevent misfires
5. 5

   Inspect spark plug wells and spark plugs
   Use a flashlight to inspect each spark plug well for oil, coolant, or debris accumulation. If any fluid is present, identify and repair the source before proceeding. Inspect visible portions of spark plugs for damage, excessive wear, or abnormal deposits. If spark plugs show wear or have exceeded service interval (30,000 miles), proceed with replacement.
6. 6

   Remove spark plugs (if replacing)
   If replacing spark plugs, use a 5/8-inch or 14mm spark plug socket with extension to remove each plug. Turn counterclockwise to loosen. Remove plugs carefully to avoid dropping debris into cylinders. Inspect each plug and note the cylinder number for diagnostic purposes.
   Torque spec

   Spark Plugs - Aluminum Head20 Nm (15 lb-ft)
7. 7

   Install new spark plugs (if replacing)
   Apply a small amount of anti-seize compound to the threads of each new spark plug, avoiding the electrode area. Thread each plug by hand into the cylinder head to prevent cross-threading. Once hand-tight, use the torque wrench to tighten to specification. Install plugs in sequence from cylinder 1 to 4.
   ⚠️CRITICAL: Do not over-torque spark plugs in aluminum heads. Excessive torque will strip threads and require costly cylinder head repair
   Torque spec

   Spark Plugs - Aluminum Head20 Nm (15 lb-ft)
8. 8

   Prepare new ignition coils
   Inspect new ignition coils for shipping damage. Apply a thin coat of dielectric grease to the inside of each coil boot where it contacts the spark plug terminal. This prevents moisture intrusion and aids future removal.
9. 9

   Install new ignition coils
   Align each ignition coil over its corresponding spark plug and cylinder. Press down firmly until the coil seats completely into the cylinder head and the boot engages the spark plug terminal. You should feel a positive engagement. Ensure the mounting bolt hole aligns with the threaded hole in the cylinder head.
10. 10

    Install and torque coil mounting bolts
    Thread each ignition coil mounting bolt by hand to ensure proper engagement. Using the torque wrench with 10mm socket, tighten each bolt to specification in a criss-cross pattern (cylinders 1-4-2-3) to ensure even seating.
    Torque spec

    Ignition Coil Bolts8 Nm (6 lb-ft)
11. 11

    Reconnect electrical connectors
    Push each electrical connector onto its corresponding ignition coil until you hear or feel a positive click indicating the locking tab has engaged. Gently tug on each connector to verify it is securely locked in place.
12. 12

    Reinstall engine cover
    Align the engine cover grommets with the mounting posts on the engine. Press down firmly on all grommet locations until the cover seats completely and sits level.

Reassembly

1. Ensure all electrical connectors are fully engaged and locked
2. Verify engine cover is properly seated on all mounting grommets
3. Double-check that no tools or parts have been left in the engine bay

Verification

• Start the engine and verify it runs smoothly without misfires or rough idle
• Check that the check engine light does not illuminate and no misfire codes are present
• Listen for abnormal engine noise or ignition system arcing sounds
• Allow engine to reach operating temperature and verify smooth operation under light acceleration
• If available, use an OBD-II scanner to verify no pending misfire codes are stored

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