Ignition Coil - Single

This procedure covers the replacement of a single ignition coil on the 6.0L V12 BiTurbo M275 engine, including accessing the coil beneath the engine cover and ensuring proper connection.

Warnings

Tools required

Parts

• Ignition coil (individual) × 1 — Use OEM specification A 002 153 30 28 or equivalent
• Spark plug (if replacement required) × 1 — Use OEM specification - NGK or Bosch per MB spec

Preparation

1. Ensure engine is completely cool to the touch
2. Turn ignition off and remove key from vehicle
3. Disconnect negative battery terminal and wait 5 minutes for system discharge
4. Identify which cylinder requires coil replacement using diagnostic trouble codes
5. Note cylinder location: front of engine is radiator side, rear is firewall side
6. Clear workspace and ensure adequate lighting for tight engine bay

Procedure

1. 1

   Remove engine cover assembly
   Remove the decorative V12 BiTurbo engine cover by loosening the cover screws at each corner. There are typically 4-6 screws securing the cover. Carefully lift the cover straight up to disengage any locating pins. Set aside in a safe location.
   Torque spec

   Cover Screws15 Nm (11 lb-ft)
2. 2

   Access affected cylinder area
   Depending on cylinder location, you may need to remove or relocate secondary covers, air intake components, or wiring harness brackets. For rear cylinders (5, 6, 11, 12), you may need to remove additional plastic covers. Remove any bracket bolts as necessary to gain access.
   Torque spec

   Bracket Bolts27 Nm (20 lb-ft)
3. 3

   Disconnect ignition coil electrical connector
   Locate the electrical connector on the ignition coil. Press the release tab and pull the connector straight up and away from the coil. Do not pull on the wiring harness itself. Note the connector orientation for reassembly.
   ⚠Connectors are fragile. Use gentle pressure on the release tab only. Forcing can break the locking mechanism.
4. 4

   Remove ignition coil mounting bolt
   Using a 5mm hex socket or appropriate tool, remove the single ignition coil mounting bolt. The bolt may be recessed deep into the cylinder head. Use an extension if needed. Keep bolt in a safe location for reinstallation.
   Torque spec

   Ignition Coil Bolts8 Nm (6 lb-ft)
5. 5

   Extract ignition coil from cylinder head
   Carefully pull the ignition coil straight up out of the spark plug well. It may require gentle twisting motion to break any seal from the rubber boot. Do not rock side-to-side excessively as this can damage the spark plug ceramic insulator below.
   ⚠If coil is stuck, do not force it. Apply slight penetrating oil around the base and wait 5 minutes before trying again.
6. 6

   Inspect spark plug well and spark plug
   Using a flashlight, inspect the spark plug well for any oil, coolant, or debris contamination. Check the spark plug electrode condition. If oil is present, there may be a valve cover gasket or tube seal issue requiring separate repair. Remove any debris with compressed air if clean and dry.
   ℹ️Oil in spark plug wells indicates valve cover gasket or spark plug tube seal failure. This must be addressed separately to prevent coil damage.
7. 7

   Replace spark plug if necessary
   If spark plug shows electrode wear, fouling, or damage, remove it using a spark plug socket with extension. Apply anti-seize compound to the threads of the new spark plug (aluminum head). Thread in by hand first to ensure proper engagement, then torque to specification.
   ⚠️CRITICAL: Apply anti-seize to spark plug threads. Aluminum heads are prone to thread galling. Never exceed torque specification.
   Torque spec

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

   Prepare new ignition coil
   Inspect the new ignition coil boot for any damage. Apply a thin layer of dielectric grease to the inside of the coil boot and around the spark plug terminal connection area. This prevents moisture intrusion and ensures proper electrical contact.
   ℹ️Use only dielectric grease, not standard grease. Dielectric grease is non-conductive and prevents electrical tracking.
9. 9

   Install new ignition coil
   Carefully lower the new ignition coil into the spark plug well, ensuring the boot properly seats onto the spark plug terminal. The coil should slide down fully until the mounting hole aligns with the cylinder head threaded hole. Ensure no wiring is pinched.
10. 10

    Secure ignition coil mounting bolt
    Insert the ignition coil mounting bolt and thread it in by hand initially. Using a torque wrench with 5mm hex socket, torque the bolt to specification. Do not overtighten as this can crack the coil housing.
    ⚠Overtightening ignition coil bolts can crack the coil housing, causing immediate failure. Use torque wrench only.
    Torque spec

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

    Reconnect electrical connector
    Align the electrical connector with the ignition coil terminal and press firmly until you hear and feel a distinct click. Gently tug on the connector to verify it is fully locked in place.
12. 12

    Reinstall access components and covers
    Reinstall any brackets, secondary covers, or intake components that were removed for access. Torque all bracket bolts to specification. Ensure all wiring harnesses are properly routed and not pinched or stressed.
    Torque spec

    Bracket Bolts27 Nm (20 lb-ft)
13. 13

    Reinstall engine cover
    Position the V12 BiTurbo engine cover back onto the engine, aligning all locating pins. Install and torque all cover screws to specification in a cross pattern to ensure even seating.
    Torque spec

    Cover Screws15 Nm (11 lb-ft)
14. 14

    Reconnect battery and clear codes
    Reconnect the negative battery terminal. Using a diagnostic scanner, clear any stored ignition misfire codes related to the cylinder that was serviced. This allows for accurate verification testing.

Reassembly

1. Verify all electrical connectors are fully seated and locked
2. Ensure no tools or parts were left in the engine bay
3. Double-check that all covers and brackets are properly secured
4. Confirm wiring harnesses follow original routing paths without stress or pinching

Verification

• Start the engine and listen for smooth idle with no misfires on the affected cylinder
• Allow engine to reach operating temperature and verify no misfires occur under load
• Using a diagnostic scanner, verify no misfire codes are present for the serviced cylinder
• Perform a test drive with gentle acceleration to confirm proper coil operation
• Re-scan for codes after test drive to ensure repair was successful
• Monitor for any check engine light illumination over the next several drive cycles

Related trouble codes on this vehicle

Codes that commonly send this job to the bay — tap one for symptoms, causes, and diagnostic steps.

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