Ignition System: Testing and Inspection

Electronic Ignition (EI) System Diagnosis

Circuit Description

The engine control module (ECM) controls the ignition coils by pulsing the ignition control (IC) circuits, which triggers an ignition coil and ignites the spark plug. The ECM controls the sequencing and the timing of each ignition coil. The ignition system consist of the following components:

* The 6 ignition coils
* The crankshaft position (CKP) sensor
* The camshaft position (CMP) sensor
* The ECM

The ignition coils use the following circuits:

* An IC circuit
* An ignition 1 voltage circuit
* A ground circuit

Test Description

The numbers below refer to the step numbers on the diagnostic table.
2. This step tests for a short to ground in the ignition 1 voltage circuit.
4. This step tests for a fault in the ignition 1 voltage circuit. It is necessary to command the fuel pump relay ON, because the fuel pump relay supplies the voltage to the ignition coils. When the fuel pump is commanded ON, the test lamp will pulse On and OFF.
5. This step test for a fault in the ground circuit of the ignition coil.
6. This step test for a fault in the IC circuit of the ignition coil.
8. This step tests for high resistance. Five ohms or more can cause can cause a driveability condition.