Ignition Coil

Fig 38 Ignition Coil:

The coil assembly consists of independent coils molded together (Fig. 38). The coil assembly is mounted on the intake manifold. High tension leads route to each cylinder from the coil. The coil fires two spark plugs every power stroke. One plug is the cylinder under compression, the other cylinder fires on the exhaust stroke. The PCM determines which of the coils to charge and fire at the correct time.

The Automatic Shutdown (ASD) relay provides battery voltage to the ignition coil.
- The PCM provides a ground contact (circuit) for energizing the coil.
- When the PCM breaks the contact, the energy in the coil primary transfers to the secondary causing the spark.
- The PCM will de-energize the ASD relay if it does not receive the crankshaft position sensor and camshaft position sensor inputs. Refer to Automatic Shutdown (ASD) Relay operation for more information.