Part 2 of 3

Chart A-3:

Ignition Circuit:

CIRCUIT DESCRIPTION:
This engine is equipped with a distributorless ignition system called Electronic Ignition (EI) system. The primary circuit of the EI consists of one ignition coil module, the ECM, and Crankshaft Position (CKP) sensor as well as the related connecting wires. The secondary circuit consists of the secondary windings of the coil module, the spark plug cable assemblies, and spark plugs.

TEST DESCRIPTION: The numbers below refer to circled numbers on the diagnostic chart.

1. The EI system uses two plugs and cables to complete the circuit of each coil. The companion spark plug cable in the circuit must be connected to ground to create a crisp blue spark on the ST-125. Connecting the companion spark plug cable to ground is also a good way to avoid overstressing the ignition coils and causing premature failure.

2. This test will determine if the 12 volts supply and a good ground is available at the ignition coil assembly.

3. This test will determine if the ECM is not triggering the ignition coils or if the ignition coil is faulty.

4. This test will determine if the ECM is at fault or the harness from ECM to ignition coil assembly is open/shorted.