P1367-P1368

IGNITION DIAGNOSTIC MONITOR

Fig. 1 Ignition Amplifiers Installed:

Fig. 2 Ignition Coil Location:

Monitoring Procedure
The ignition amplifier for each bank sends an output to the ECM when the ignition has operated correctly. If greater than a set number of pulses are not seen from the amplifier (indicating missing ignition pulses) then the ignition circuit for that bank is judged to be faulty. The appropriate diagnostic trouble code (DTC) is stored immediately.

Ignition Amplifiers
The ignition amplifiers receive ignition signals from the ECM and controls the primary current of the ignition coils. The switching of the current generates a high voltage at the secondary windings of the ignition coils.

The ignition monitoring circuit senses the primary current of the ignition coils and informs the ECM that correct ignition has occurred. If the information indicates incorrect ignition, the ECM stops fuel injection to the relevant bank and provides "limp home" mode for the other bank.

Fig. 1 Ignition Coil:

Fig. 2 Ignition Amplifier:

Fig. 3 Ignition Coil Sectional:

Structure of Ignition Amplifier
The ignition coil provides the high tension spark to ignite the fuel / air mixture in each cylinder.

The ignition coil pack contains three separate ignition coils which are controlled by the igniter through three coil leads. Each ignition coil ignites two spark plugs simultaneously, one spark in the compression stroke and one on the exhaust stroke.

The spark plug ignited on the exhaust stroke uses very little of the ignition coil's stored energy, the majority being used on the compression stroke. Since these two spark plugs are connected in series, the igniting voltage of one spark plug will be negative with respect to ground, while the other will be positive with respect to ground.