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

Electrical Information Reference

Scan Tool Reference

Special Tools Required

J 26792 Spark Tester

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 fuse that supplies 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 the engine bank, for a short to ground.

3. Disconnect the ignition module/coil, and the 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 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.