General System Description

Image Legend:
1. Power output stage.
2. Dual ignition coils.
3. Camshaft Position Sensor.
4. Knock Sensor I.
5. Knock Sensor II.
6. Connection to total system.

OPERATION:
The fully-electronic ignition system dispenses with rotating parts, relying instead upon exclusively electronic means to regulate ignition timing and voltage.
On the 6-cylinder engine, the three separate ignition coils each trigger two spark plugs. The Engine Control Module determines the optimum ignition timing based on signals from the two knock sensors and the engine-speed sensor.
The system can also detect and rectify preignition at individuals cylinders.
The Power output stage is not integrated within a single housing with the dual ignition coils, rather it is a separate component.
On the V6-engine every 2 cylinders are supplied by one ignition coil.

OBD II MONITORS:
- The electrical signal from the two knock sensors G61 and G66.
- Ignition system operation, based on the misfire recognition function.

Frequent misfiring can indicate a malfunction within the ignition system. By following the steps in the diagnosis procedures it is possible to localize the precise source of the problem through a process of elimination.

Electrical Circuit - Dual Ignition Coils With Power Output Stage N122:

SYSTEM COMPONENTS:
Dual Ignition Coils with Power Output Stage N122:
The distributorless ignition used on the V6 consists of three dual ignition coils - and an output amplifier circuit. Each output amplifier circuit controls the corresponding dual ignition coil. Each of the dual coils furnishes the firing voltage to a pair of cylinders. The respective pairings are cylinders 1+6, 2+4, and 3+5.

Knock Sensors G61 & G66:

Electrical Circuit - Knock Sensors G61 & G66:

Knock Sensors G61 and G66:
The electronic ignition-timing control perates in combination with selective preignition control for the individual cylinders. The ability to detect knock at the respective cylinders is enhanced through installation of two knock sensors. The process used to identify the affected cylinder(s) is assisted by signals from the camshaft Position sensor.
The system responds to recognized preignition at a given cylinder by initiating gradual reductions in the timing advance angle. The system continues to move back the timing until the knock disappears.
The system responds to malfunctions at G61 and/or G66 by retarding the ignition angle for all cylinders and enriching the mixture.