This ignition system uses individual ignition module/coil assemblies for each cylinder. The engine control module (ECM) controls the spark events by transmitting the timing pulses on the ignition control (IC) circuits to the individual ignition module/coil assemblies in firing order sequence. Each ignition module/coil has the following circuits:

Schematic Reference

Engine Controls Schematics

Connector End View Reference

Component Connector End Views

Electrical Information Reference

Scan Tool Reference

Control Module References for scan tool information

Special Tools

Observe the Engine Controls Schematic for the ignition module/coils, and review the Ignition System Specifications to verify the following concerns:

1. Turn OFF the ignition.

Important: This engine application uses 2 fuses, one for each bank, to supply ignition 1 voltage to the ignition module/coil assemblies and also to the fuel injectors. A good indication that a fuse is open is that all 4 misfire counters are incrementing on one side of the engine

2. Inspect both fuses that supply ignition voltage to the ignition module/coils.

⇒	If a fuse is open, test all 8 ignition voltage circuits to the ignition module/coils or the fuel injectors on that engine bank, for a short to ground.

3. Disconnect the 4 ignition module/coil, and the 4 fuel injector electrical connectors, for the engine bank that has the open fuse.
4. Replace the open fuse with a new fuse.
5. Ignition ON, engine OFF.
6. Reconnect each ignition module/coil, and fuel injector electrical connectors, one at a time.

⇒	If the fuse opens when connecting an ignition module/coil or fuel injector electrical connector, then replace the component that caused the fuse to open.

7. Ignition OFF, disconnect the appropriate ignition module/coil electrical connector.
8. Ignition ON, verify that a test lamp illuminates between the ignition voltage circuit and ground.

⇒	If the test lamp does not illuminate test the ignition voltage circuit for an open/high resistance.

9. Verify that a test lamp illuminates between the ignition module/coil ground circuit and B+.

⇒	If the test lamp does not illuminate, test the ignition module/coil ground circuit for an open/high resistance.

10. Inspect and measure the resistance of the spark plug wire. Refer to Spark Plug Wire Inspection and Ignition System Specifications.

⇒	If the resistance value is not within the specified range, or does not pass the inspection, replace the spark plug wire.

11. Exchange the misfiring cylinder, ignition module/coil assembly with the ignition module/coil assembly from a non-misfiring cylinder.
12. Start and idle the engine. Observe the misfire counters on the scan tool.

⇒	If the misfire transfers with the suspect ignition module/coil, then replace the ignition module/coil assembly.

⇒	If the misfire does not transfer with the suspect ignition module/coil, then measure the resistance of the IC circuit. The IC circuit should measure less than 5 ohms. If the circuit tests normal, replace the ECM.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.