Ignition Coil: Description and Operation

Fig 3 Ignition Coil Packs:

Fig 4 Ignition Coil Packs:

WARNING: The electronic ignition system generates approximately 40,000 volts. Personal injury could result from contact with this system.

IGNITION COILS
The electronic ignition system uses two epoxy filled coil packs mounted on a bracket at the rear of the engine (Fig. 3) and (Fig. 4). The coil pack on the left side, contains three separate coils and fires cylinders 1, 2, 3, 4, 6, and 7. The coil pack on the right side, contains two individual coils and fires cylinders 5, 8, 9, and 10. When one of the coils discharges, it fires two cylinders at the same time (one cylinder on its compression stroke, the other on its exhaust stroke).

The PCM energizes the individual coils in each pack by providing a ground path to the particular coil. The PCM determines cylinder identification from the crankshaft position sensor and camshaft position sensor inputs.

CIRCUIT OPERATION
There are two ignition coil packs used on this vehicle. The ignition coil pack used to fire spark plugs 1, 2, 3, 6, 8, and 9 consists of three separate coils molded together. The coil pack used to fire spark plugs 4, 5, 7, and 10 consists of two coils molded together.

Power for the ignition coils is supplied on circuit A142 when the contacts in the Automatic Shut Down (ASD) relay are CLOSED. Battery voltage for the contact side of the ASD relay is supplied on circuit A14. This circuit is HOT at all times and protected by a 20 amp fuse located in cavity 15 of the Power Distribution Center (PDC).

Power for the coil side of the ASD relay is supplied on circuit F12. This circuit is HOT when the ignition switch is in the START or RUN position. Ground for the coil side of the relay is controlled by the Powertrain Control Module (PCM) on circuit K51.

When the PCM supplies a ground path for circuit K51 the contacts in the ASD relay CLOSE connecting circuits A14 and A142. Circuit A142 powers the ignition coils and is spliced internal to the PDC to supply an ASD relay energized input to the PCM.

Ground for the ignition coils is controlled by the PCM at the BLACK connector. Circuit K19 is the ground circuit for coil driver #1 and connects to cavity A7 of the PCM.

Circuit K17 is the ground circuit for coil driver #2 and connects to cavity A9 of the PCM.

Circuit K18 is the ground circuit for coil driver #3 and connects to cavity A3 of the PCM.

Circuit K32 is the ground circuit for coil driver #4 and connects to cavity A1 of the PCM.

Circuit K43 is the ground circuit for coil driver #5 and connects to cavity A5 of the PCM.