Parts for your 2020 Holden Commodore-Ignition coils

2020 Holden Commodore ignition coils

Ignition coils are absolutely relevant to the 2020 Holden Commodore ZB in its petrol forms. Technical references including the Holden ZB Commodore Service Manual (GM Global Service Information), GM 2.0L LTG ignition system description, and GM 3.6L LGX ignition system description specify coil‑on‑plug ignition for these engines. Each spark plug has its own coil mounted directly on top to deliver a strong, precisely timed spark. Only the 2.0L diesel used in some markets runs compression ignition and glow plugs instead of ignition coils, for Australian and New Zealand 2020 petrol models, ignition coils are fitted and part of normal servicing considerations.

The job of an ignition coil is to step battery voltage up to tens of thousands of volts and fire the spark plug under load. Coil‑on‑plug setups reduce high‑tension leads, cut energy losses, and let the ECU control timing and dwell per cylinder for smooth running and better fuel economy. On the 2.0L turbo you’ll find four coils, the 3.6L V6 runs six.

Coils aren’t a scheduled replacement item, but they’re worth checking whenever plugs are replaced or a misfire pops up. Follow the factory logbook for spark plug intervals, as fresh plugs protect coils from overworking. When servicing, look for cracking on the coil body, heat‑tired boots, oil in plug tubes (from rocker cover seals), or green/white corrosion on connectors. If a coil fails, the check engine light will usually flag a misfire (common codes P0300–P030X) or an ignition circuit fault.

• Typical symptoms of a tired coil: rough idle, stumble under load, hard starting, poor fuel economy, and sulphur smell from the exhaust.
• Good practice: replace the faulty coil with an OE‑quality unit, and always fit new plugs if they’re due. On high‑kilometre cars with repeated coil faults, a full set can save future workshop visits.
• Avoid pressure‑washing the engine bay, keep connectors clean and latched, and use a light touch of dielectric grease on the boot during refit.

Replacement is straightforward for a trained tech: remove the engine cover, unplug the connector, lift the coil, swap in the new unit, and refit to the manufacturer’s torque spec. A quick road test and scan for codes confirms the fix. With quality parts and healthy plugs, ignition coils often run well past 100,000 km without dramas.

Popular questions

How many ignition coils does a 2020 Holden Commodore have?

The 2.0L turbo petrol has four coil‑on‑plug units (one per cylinder). The 3.6L V6 has six. A diesel variant (where fitted in some markets) uses no ignition coils, relying on glow plugs instead.

When should the ignition coils be replaced?

There’s no fixed kilometre interval. Replace coils when there’s a confirmed misfire, ignition fault code, or physical damage. Stick to the logbook spark plug interval, fresh plugs reduce coil stress and prevent premature failures.

Is it okay to keep driving with a misfiring coil?

Best not. Driving with a misfire can damage the catalytic converter, increase fuel use, and leave the car down on power. It’s smarter to diagnose the fault promptly and sort the coil or plug before it snowballs.