Parts for your 2017 Subaru Impreza-Ignition leads

2017 Subaru Impreza ignition leads — are they used?

For the 2017 Subaru Impreza, traditional ignition leads (spark plug leads/high-tension leads) are not fitted or required. Technical documentation for the 2017MY Impreza with the FB20-series 2.0‑litre engine specifies a coil‑on‑plug (COP) ignition system, where each spark plug has its own dedicated ignition coil mounted directly on top of the plug. That setup eliminates the need for separate high‑tension leads.

This isn’t just marketing speak — it’s how the car is built. The Subaru Workshop Manual for the 2017MY Impreza (GK/GT platform) under the Ignition System section details individual cylinder ignition coils and spark plugs, with no “high‑tension cord” service item listed. Genuine Subaru parts catalogues for the same model list ignition coil assemblies and spark plugs, but no ignition leads. Major ignition component catalogues (e.g., NGK) likewise specify coil‑on‑plug parts for this model year, again with no listing for leads. These technical sources all align: there are no ignition leads on this vehicle.

Why did Subaru go this way? COP systems improve spark energy and timing accuracy, cut electrical losses that can occur through long leads, reduce electromagnetic interference, and simplify diagnostics. Fewer components also means fewer wear items to chase during a service. For owners who came looking to replace “leads,” the good news is there’s nothing to replace there.

What should be looked after instead? The service focus moves to the spark plugs and the individual ignition coils:

• Spark plugs: Replace at the interval in the owner’s/service manual (commonly around 100,000 km for long‑life iridium in local schedules). Use the specified plug type and gap, and tighten to the factory torque.
• Ignition coils: Inspect during services for cracking, heat damage, corrosion on terminals, or oil in the plug tubes. Make sure coil boots seal properly and are refitted cleanly. A dab of suitable dielectric grease on the boot can help future removal.
• Misfire checks: If there’s a misfire, scan for fault codes, inspect the plugs, and if needed swap the suspected coil to another cylinder to see if the fault follows the coil.

So, for a 2017 Impreza, “ignition leads” aren’t a thing. Keeping quality plugs in it and ensuring the coil‑on‑plug units are healthy is the right way to maintain a smooth, efficient Aussie or Kiwi daily.

Popular questions

Does a 2017 Subaru Impreza have ignition leads?
No. The 2017 Impreza’s FB20 engine uses a coil‑on‑plug system, with an individual coil sitting directly on each spark plug, so there are no high‑tension leads to replace.

What do you service instead of ignition leads on a 2017 Impreza?
Focus on the spark plugs and the coil packs. Replace plugs at the scheduled interval in the maintenance guide, and inspect each coil and boot for heat damage, cracking, or contamination. Address any oil in the plug tubes and ensure boots seal properly.

How do you diagnose a misfire if there are no leads?
Read fault codes, check plug condition and gap, and examine each coil. If needed, swap a coil to another cylinder — if the misfire moves with it, the coil is likely the culprit. Always rule out basics like vacuum leaks and fuel quality as well.