Parts for your 2019 Subaru Impreza-Ignition coils

2019 Subaru Impreza ignition coils — purpose, care and when to replace

Based on technical references including the Subaru 2019MY Impreza Service Manual (Ignition System), Subaru’s Technical Information System (STIS), and OEM parts catalogues for the FB20 2.0L petrol engine, the 2019 Subaru Impreza is fitted with individual coil-on-plug ignition coils (one per cylinder). These sources clearly list, diagram and specify testing procedures for the ignition coils on this model, so ignition coils are absolutely relevant to any servicing or fault diagnosis on a 2019 Impreza.

On this car, the ignition coils sit directly on top of each spark plug. Their job is to take the 12-volt battery supply and step it up to a high-voltage spark at precisely the right moment, as commanded by the engine control unit. Good coils mean clean starts, smooth idle, strong fuel economy and snappy throttle response. Tired or failing coils show up as misfires, rough running and a glowing check engine light.

There’s no set “replace-by” interval for coils on the Impreza, they’re a condition-based item. During regular servicing, it’s smart to check for oil or moisture around the coil boots, look for heat cracking, and ensure the connectors are snug. Pair coil health with fresh spark plugs at Subaru’s recommended interval, and avoid blasting water under the bonnet. If one coil fails at moderate kilometres, it’s fine to replace just the faulty unit, at higher kilometres some owners choose to replace the full set for peace of mind.

• Common symptoms of a failing coil on a 2019 Impreza:
  • Rough idle, hesitation or a flat spot under load
  • Hard starting or increased fuel use
  • Check engine light with codes like P0300–P0304 or P0351–P0354
  • Raw fuel smell from the exhaust during misfire events
  • Visible arcing, heat damage or oil contamination at the coil boot

When replacing, use quality OE-spec coils, keep the coil boots clean and dry, and apply a tiny smear of dielectric grease inside the boot to help prevent tracking. Seat each coil fully onto the plug, snug the hold-down fastener to spec, and recheck the connector click. After installation, clear fault codes and road test to confirm the misfire counter stays at zero. A well-looked-after set of coils in a 2019 Impreza will typically run for many tens of thousands of kilometres without fuss.

Popular questions

What are the first signs an ignition coil is going on a 2019 Subaru Impreza?
Owners usually notice a shudder at idle, a stumble when accelerating, or the check engine light. Scan tools often show a cylinder-specific misfire. If the issue improves in the wet or gets worse when hot, that’s another hint the coil or boot insulation is breaking down.

Should all four coils be replaced at once?
Not necessarily. If one coil fails at modest kilometres, replacing just that coil is fine. If the car is higher mileage or multiple coils test weak, doing the full set can prevent repeat visits and keep performance consistent.

How often should coils be inspected on the Impreza?
Have them visually checked at regular services, especially when spark plugs are due. Look for heat damage, cracking, or oil in the plug tubes. Keep the area dry and clean to extend coil life.