If you're noticing misfires, poor fuel economy, reduced engine performance, or ignition-related diagnostic trouble codes (DTCs), a failing ignition coil is likely the cause. Late-model BMWs, such as the E60 M5, E63 M6, and E64 M6, use a coil-on-plug ignition system, where each cylinder has its own coil and spark plug for efficient ignition. When a coil fails, the affected cylinder won't receive a spark and will misfire. Even if the misfire doesn’t trigger a DTC, you’ll still feel the difference in engine performance—rough idling, hesitation during acceleration, or a strong fuel smell. To avoid these issues, we recommend replacing your ignition coils every 40,000-60,000 miles.
The S85 engine uses a specialized ignition system called Ionic Current Control, which differs from traditional knock sensors. BMW engineers developed this system to more accurately detect pre-ignition and misfires in the high-revving, ten-cylinder S85. Instead of relying on conventional knock sensors, the system uses each spark plug to measure current after the power stroke, transmitting that data to the Ionic Current Control Unit (ICC). This allows for precise monitoring of combustion events. To support this, the S85’s ignition coils are specially designed with a modified “pencil” shape and lack a Zener diode in the secondary winding, allowing for accurate current measurements without triggering fault codes in the engine control unit (DME). These ignition coils are manufactured to the exact specifications of the OE Ionic Current Control-compatible ignition coil, and will not trigger ignition-related fault codes in the DME.
Bavarian Autosport ignition coils are engineered for reliability, delivering a consistent, long-lasting spark. These high-quality OE replacement coils are specifically designed for your S85-powered E60 M5, E63 M6, or E64 M6. Constructed with durable, heat-resistant plastic and featuring premium rubber spark plug boots, each boot is pre-lubricated with dielectric grease to ensure smooth installation and prevent corrosion.
Whether you're fixing misfires, replacing a faulty coil, or performing preventative maintenance on your S85 ignition system, trust Bavarian Autosport ignition coils for a dependable, lasting repair.
FEATURES:
Durable, heat-resistant plastic: Built to withstand extreme temperatures and harsh driving conditions for long-lasting durability. Pre-lubricated, high-quality rubber boots: Prevent moisture and corrosion while ensuring smooth, easy installation. OE-quality construction: Meets or exceeds original equipment standards for perfect fit, reliable performance, and effortless installation.
We recommend replacing the rubber boot that connects the ignition coil to the spark plug. Sometimes a bad coil may just be a broken or damaged connector boot. This is especially true on cars with a leaking valve cover gasket where the oil has contamintated the rubber boot and the electrical parts inside. This boot can be replaced on its own without having to buy a whole new coil. This part is also useful if you purchased a coil that did not come with a new boot. 
