Parts for your 2015 Lexus Is-Ignition coils

2015 Lexus IS ignition coils — what they do and how to look after them

Ignition coils are definitely fitted to the 2015 Lexus IS range. Lexus/Toyota technical sources, including the 2015 IS Repair Manual (Ignition System – “Ignition Coil Assembly [Coil-On-Plug]”) and the Toyota Electronic Parts Catalogue, specify a coil-on-plug setup with one coil per cylinder across the petrol line-up (IS 250, IS 350 and IS 300h). DENSO catalogues also list direct-fit coil-on-plug units for these engines. So yes — ignition coils are relevant to this model year.

The job of each ignition coil is to step 12-volt battery power up to the high voltage needed to fire the spark plug, right at the top of the cylinder. Because the 2015 IS runs coil-on-plug, there’s no traditional distributor or long leads — it’s cleaner, more reliable, and lets the engine computer control spark more precisely for power, economy and emissions.

Coils aren’t a routine replacement item, but they do live a hard life under the bonnet. During scheduled servicing, especially when the spark plugs are due, it’s smart to inspect the coils and boots for cracks, carbon tracking or oil in the plug wells. Spark plugs are typically due somewhere around 90,000–120,000 km depending on variant and local schedule, that’s the perfect time to check the coils because they’re already off the plugs.

Signs a coil is on the way out include a rough idle, hesitation under load, poorer fuel economy and a glowing check engine light. Common OBD-II clues are cylinder misfire codes (P0300 series) or specific coil circuit faults (P0351–P0356 depending on engine and cylinder). A quick workshop trick is to swap a suspected coil to another cylinder and see if the misfire follows.

When replacement’s needed, sticking with quality OE-spec coils (commonly DENSO for Lexus) helps avoid repeat issues. Coils can be replaced individually if only one has failed, though higher-kilometre cars may benefit from doing any obviously tired mates at the same time. Keep the plug wells clean, seat the connectors firmly, and avoid pressure-washing the engine bay to reduce moisture-related failures.

• Check coils whenever plugs are serviced.
• Fix misfires promptly to protect the catalytic converters.
• Use OEM-equivalent parts for best longevity and smooth running.

Looked after properly, ignition coils on a 2015 IS often run well past 150,000 km, keeping that V6 or hybrid four humming along nicely.

Popular questions

Do all 2015 Lexus IS models use ignition coils?
Yes. The 2015 IS 250 and IS 350 V6 engines and the IS 300h hybrid’s petrol engine all use coil-on-plug ignition coils, one per cylinder. There was no diesel option in this generation for most markets, so every 2015 IS sold locally uses ignition coils.

How often should ignition coils be replaced on a 2015 Lexus IS?
There’s no fixed interval — coils are typically replaced only when faulty. Have them inspected whenever spark plugs are changed (often around 90,000–120,000 km depending on engine and service schedule). Replace a failing coil promptly to avoid misfires and potential catalytic converter damage.

Can a bad ignition coil damage other components?
It can. A persistent misfire from a weak coil can overheat and damage the catalytic converters and oxygen sensors. If the check engine light is flashing or it’s running rough, avoid extended driving and get it checked sooner rather than later.