Ignition System: Testing and Inspection
ELECTRONIC IGNITION (EI) SYSTEM DIAGNOSISCIRCUIT 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
- The IC circuit
- A low reference signal
Each ignition module/coil connects directly to its spark plug through a wire spring conductor internal to the spark plug boot. The IC circuits transmit timing pulses from the powertrain control module (PCM) to each ignition module/coil assembles in the proper sequence for the spark plug firing event. 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
- This electronic ignition (El) system diagnostic table assumes that the vehicle battery is fully charged.
- 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 isolating an intermittent condition. Replace any worn or torn spark plug boots or seals.
- If the ODD INJ or EVEN INJ fuse opens, this will also result in the loss of ignition 1 voltage to the odd or even fuel injectors.
TEST
