Ignition Discharge Module: Ignition

The ignition discharge module is located on the camshaft cover above the spark plugs. It contains 4 ignition coils, the secondary winding of which are connected to the spark plugs.

The ignition discharge module is powered with B+ from the main relay and is grounded to grounding point G7.

When the main relay operates, B+ is fed to the ignition discharge module, which converts the 12V to 400V DC and stores it in a capacitor. The 400V is connected to one of the poles of the primary winding on each of the 4 ignition coils.

There are 4 trigger leads running from the control module to the ignition discharge module connected as follows:

• Cylinder 1 is connected to control module pin 7.
• Cylinder 2 is connected to control module pin 54.
• Cylinder 3 is connected to control module pin 55.
• Cylinder 4 is connected to control module pin 8.

When the control module grounds pin 7, the other pole on the primary winding of the ignition coil for cylinder 1 will be connected to the B+ input on the ignition discharge module. 400V is stepped up to maximum 40kV in the ignition coil for cylinder 1. Ignition takes place for cylinder 2, 3 and 4 in the same way.