Electronic Ignition (EI) System Diagnosis
ELECTRONIC IGNITION (EI) SYSTEM DIAGNOSIS
CIRCUIT DESCRIPTION
The ignition system utilizes an individual module/coil for each spark plug. The following 4 circuits support each ignition module/coil assembly.
- The ignition 1 voltage circuit
- The ground circuit
- Ignition control (IC) circuit
- Low reference circuit
Each ignition module/coil connects directly to its spark plug through a wire spring conductor internal to the spark plug boot. The IC circuits transmits timing pulses from the engine control module (ECM) to each ignition module/coil assembles in the proper sequence for the spark plug firing event. The ECM 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
- This Electronic Ignition (EI) System Diagnostic table assumes that the battery is fully charged. Refer to Battery Inspection/Test in Starting and Charging. Battery Inspection/Test
- Other electrical, fuel, or mechanical conditions can cause an engine to crank but does not run, or set a DTC P0300 misfire code.
- 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 insolating an intermittent condition. Replace any worn or torn spark plug boots or seals.
- If the ODD coils or EVEN coils fuse opens, this will also result in the loss of ignition 1 voltage to the odd or even fuel injectors.
TEST
