Ignition Coils

WARNING: This page is about a different car, the 2015 Jaguar XF, 2014 Jaguar XF, and 2013 Jaguar XF. However, it is still accessible from the selected car via links, so may be relevant.

The ignition coils are installed in the cylinder head covers, under the ignition coil covers. Each ignition coil locates on a spark plug and is secured to the related cylinder head cover with a single screw. Each ignition coil incorporates a three pin electrical connector for connection to the engine harness.

The ignition coil contains a primary and a secondary winding. The primary winding receives electrical power from the ignition relay in the EJB. A power stage in the primary winding allows the ECM to interrupt the power supply, to induce a voltage in the secondary winding which is discharged via the spark plug. A diode in the ground side of the secondary winding reduces any undesirable switch-on voltage, to prevent misfiring into the intake manifold. The power stage limits the maximum voltage and current in the primary winding, to protect the power stage and limit the voltage in the secondary winding.