Ignition Coil Primary Circuit

IGNITION COIL PRIMARY CIRCUIT

When Monitored
With battery voltage greater than 8 volts during engine cranking or greater than 12 volts with engine running, and with engine rpm less than 3000, and none of the coils in dwell when checked.

Set Condition
Peak current is not achieved with 5.75 ms of dwell. It takes 3 seconds during cranking or up to 6 seconds while running to set.

Theory of Operation
The ignition coil is supplied 12 volts from the ASD relay. The PCM controls the individual primary circuits:
- Cavity 19 controls coils #1 and #4.
- Cavity 17 controls coils #2 and #5.
- Cavity 18 controls coils #3 and #6.
The amount of dwell time is based on crankshaft speed and camshaft position.

Possible Causes
- Open or shorted ignition coil driver circuit.
- Open ignition coil primary.
- Open ASD output circuit.
- Failed PCM.