Ignition Coil

WARNING: This page is about a different car, the 2018 Land Rover Discovery Sport. However, it is still accessible from the selected car via links, so may be relevant.

The ignition coils are installed in the cylinder head, under the Noise, Vibration and Harshness (NVH) cover. Each ignition coil locates on a spark plug and is secured to the camshaft carrier with a single screw. Each ignition coil incorporates a 3 pin electrical connector for connection to the engine wiring harness.

Each ignition coil contains a primary and a secondary winding. The primary winding receives the power supply from the Powertrain Control Module (PCM) relay in the Engine Junction Box (EJB). A power stage in the primary winding allows the PCM to interrupt the power supply. This induces a voltage in the secondary winding and thus the spark plug.

A diode in the ground side of the secondary winding reduces any undesirable switch-on voltage, to prevent misfiring into the combustion chamber. The diode limits the maximum voltage and current in the primary winding, to protect the power stage and limit the voltage in the secondary winding.