Parts for your 2015 Subaru Forester-Ignition leads

Understanding Ignition Leads on the 2015 Subaru Forester

When it comes to the ignition system of the 2015 Subaru Forester, it's important to know that traditional ignition leads, also called spark plug wires, are not actually used on this model. Instead, the 2015 Forester employs a more modern ignition system design that's quite different from older vehicles.

So, why does the 2015 Subaru Forester not use ignition leads? The answer lies in the evolution of ignition technology. In older cars, ignition leads carried electrical current from the distributor or ignition coil to the spark plugs, delivering the necessary spark to ignite the air-fuel mixture inside the engine. These leads were made of insulated wire to withstand high voltage and heat, but over time they could degrade, crack, or cause performance issues.

However, many newer vehicles like the 2015 Subaru Forester use a coil-on-plug (COP) ignition system. This system removes the need for separate ignition leads entirely. Instead of a distributor with a single coil sending high-voltage current through wires, the Forester has an individual ignition coil mounted directly on top of each spark plug. These coils generate the spark right at each plug's location, eliminating the cable required to transmit electrical current across the engine.

This shift to coil-on-plug technology provides several benefits. It simplifies the engine bay by reducing parts and wiring, improves spark timing accuracy, cuts down the chance of electrical leakage or interference, and generally results in more reliable ignition performance. It also means less regular maintenance for things like ignition leads, since they are simply not there.

For Forester owners, this means they won't need to worry about ignition leads wearing out or needing replacement. That said, while the ignition leads themselves don't exist, the coil-on-plug units do require attention as part of regular servicing to ensure the vehicle runs smoothly.

Replacing or maintaining ignition leads used to be a common part of routine servicing. For older vehicles with ignition leads, regular checks were essential because faulty leads could cause engine misfires, rough idling, poor fuel economy and increased emissions. Signs that ignition leads were wearing out included visible cracks in the insulation, excessive resistance detected on testing, or engine performance problems. Replacing the leads with good-quality ones could restore spark delivery and engine smoothness.

With the 2015 Subaru Forester's coil-on-plug system, while you don't have ignition leads, you still have ignition coils. These can fail or wear out over time due to heat, vibration and electrical load, leading to similar problems such as misfires or trouble starting the engine. It's important for servicing routines to include inspecting the ignition coils and associated connectors.

Typically, technicians will test coil resistance and output during scheduled services or when drivability issues arise. If a coil shows signs of failure, it's recommended to replace it promptly to prevent damage to the catalytic converter and maintain optimal engine performance. Fortunately, coil replacement on this model is usually straightforward since they are mounted directly on the spark plugs.

To keep your 2015 Subaru Forester running tip-top, regular servicing as advised in the owner's manual should cover ignition system checks. Paying attention to rough running, stalling, or a persistent engine warning light can help catch ignition coil issues early. While you won't be replacing ignition leads per se, maintaining the ignition system as a whole is just as important.

In essence, the absence of ignition leads in the 2015 Subaru Forester is a good example of how automotive technology keeps advancing to make vehicles more efficient and easier to maintain. The coil-on-plug ignition system not only boosts performance but also reduces the number of parts that can wear out and cause problems. So while traditional ignition leads have their place in older cars, the Forester has moved on to a simpler, more reliable setup that helps keep the engine firing smoothly for many kilometres down the road.