Ignition System: Testing and Inspection

CIRCUIT DESCRIPTION
There are two separate ignition module assemblies, one for each bank of cylinders. Each assembly contains an ignition control (IC) module and four ignition coils. Both IC modules consist of the following circuits:
- The ignition 1 voltage circuit
- The ground circuit
- The IC circuits for cylinders 1, 3, 5, 7 on bank 1 ignition module
- The IC circuits for cylinders 2, 4, 6, 8 on bank 2 ignition module
- The IC module low reference circuit

Each ignition coil connects directly to its spark plug through a wire spring conductor housed in a short spark plug boot. The IC circuits transmit timing pulses from the powertrain control module (PCM) to the IC modules which triggers the ignition coils in the proper sequence for spark plug firing. The PCM monitors each IC circuit for improper voltage levels. If an improper voltage level is detected on an IC circuit a DTC will set.

DIAGNOSTIC AIDS
- Other electrical, fuel, or mechanical conditions can cause an engine to crank but does not run, or set a DTC P0300 misfire code.
- This Electronic Ignition (EI) System diagnostic table assumes that the vehicle battery is fully charged. Refer to Battery Inspection/Test in Starting and Charging. Battery Inspection/Test
- An ignition coil, boots, or spark plugs may misfire only when moisture is present. Although difficult to test on this engine, selectively wetting down parts of the ignition system and monitoring for a misfire may help in isolation an intermittent condition. Replace any worn or torn spark plug boots or seals.
- Intermittent conditions-Refer to Intermittent Conditions. Intermittent Conditions

TEST DESCRIPTION

Steps 1-3:

Steps 4-7:

Steps 8-9:

Steps 10-11:

Steps 12-15:

Steps 16-17:

Steps 18-19:

Steps 20-21:

Steps 22-23:

Steps 24-28:

Steps 29-36:

Steps 37-46:

Steps 47-48:

The numbers below refer to the numbers in the diagnostic table.
3. This step tests for a short to battery positive voltage on the ignition 1 voltage circuit. When the ignition is turned OFF, the test lamp should not illuminate at the COIL/MDL fuse.
18. The Spark Tester places a higher load, up to 25,000 volts, on the secondary ignition than a normal spark plug.