Parts for your 2018 Mitsubishi Outlander-Ignition coils

2018 Mitsubishi Outlander ignition coils — what they do and when to replace them

Ignition coils are relevant to most 2018 Mitsubishi Outlander models. Technical sources including the Mitsubishi Motors 2018 Outlander Service Manual (Engine Electrical/IGN section), the Mitsubishi ASA electronic parts catalogue (listing plug-top ignition coils for petrol 4B11/4B12 and 6B31 engines), and application catalogues from OEM coil suppliers (e.g., DENSO and NGK) all specify coil-on-plug units for the petrol and PHEV variants. The diesel 2.2 DI‑D (4N14), being compression‑ignition, does not use ignition coils per diesel engine design and Mitsubishi diesel service literature.

On the 2018 Outlander petrol and PHEV, ignition coils are the quiet achievers sitting right on top of the spark plugs. Their job is to take the battery’s 12 volts and turn it into the thousands of volts needed to jump the spark plug gap and light off the air–fuel mix. Mitsubishi uses a coil‑on‑plug setup here, which keeps the high voltage right at the plug for a strong, clean spark and less energy loss.

They’re generally maintenance‑free, but they do live in a hot spot under the bonnet and eventually wear. Typical signs they’re on the way out include a rough idle, hesitation under load, harder starts, poorer fuel economy, and the check engine light with misfire codes (like P0301–P0304) or coil circuit codes (P0351–P0354 on four‑cylinder models). If the Outlander is a four‑cylinder petrol or PHEV, it’ll have four coils, V6 models have six. Diesel models don’t use coils at all.

There’s no fixed replacement interval for coils, so most owners just replace the faulty unit when a misfire is confirmed. That said, it’s smart to:

• Inspect coils whenever the spark plugs are changed (often around 90,000–100,000 kilometres for iridium plugs, follow the vehicle’s service schedule).
• Check the rubber boots for cracks, carbon tracking, or oil contamination from a leaking rocker cover gasket.
• Use quality OEM‑equivalent coils and the correct plugs and gap to keep the ignition system happy.
• Avoid soaking coils with water or solvent when cleaning the engine bay.

When replacing, work one cylinder at a time, keep connectors clean and properly seated, and don’t over‑tighten the coil hold‑down bolts. If one coil has failed on a high‑kilometre vehicle, some owners choose to replace the full set to restore smooth running and avoid repeat visits. Prompt attention to misfires also protects the catalytic converter from unburnt fuel damage. Treated well, coils can last many years and hundreds of thousands of kilometres.

Popular questions about 2018 Mitsubishi Outlander ignition coils

How many ignition coils are in a 2018 Outlander?
Petrol and PHEV four‑cylinder models use four coil‑on‑plug units (one per cylinder). V6 petrol models use six. The 2.2 DI‑D diesel doesn’t have ignition coils because it relies on compression ignition rather than spark.

When should the coils be replaced?
There’s no scheduled interval. Replace coils when they cause a verified misfire or show damage. It’s worth inspecting them when changing spark plugs (often around 90,000–100,000 km) and replacing any suspect boots. High‑kilometre vehicles may benefit from replacing the set for long‑term reliability.

Can a failing coil damage the catalytic converter?
Yes, driving with a persistent misfire can send unburnt fuel into the exhaust and overheat the cat. If the check engine light is flashing or the engine is clearly missing, limit driving and have the fault diagnosed and repaired promptly.